UNIVERSITY 
CAUFOIW. 

SAN  DIEGO 


u  iiiliiiilKiliii 

u      3  1822  01364  0065     & 

•-n  .»v»u_nf  onurunniM 

LIFE    AND    DEATH 


BV 
A.  jDASTRE, 

PROFESSOR  OF   FHTSIOLOGT  AT  THB  SOKBONXR 


TRANSLATED   BY 

W.  J.  GREENSTREET,  M.A.,  F.R.A.S. 


THE  WALTER  SCOTT  PUBLISHING  CO.,  LTD., 

PATERNOSTER  SQUARE,  LONDON,  E.C 

CHARLES  SCRIBNER'S  SONS, 

153-157     FIFTH     AVENUE,     NEW    YORK. 

1911 


P|REFACE. 

THE  educated  and  inquiring  public  of  the  present 
day  addresses  to  the  experts  who  have  specialized 
in  every  imaginable  subject  the  question  that  was 
asked  in  olden  times  of  Euclid  by  King  Ptolemy 
Philadelphus,  Protector  of  Letters.  Recoiling  in 
dismay  from  the  difficulties  presented  by  the  study 
of  mathematics  and  annoyed  at  his  slow  progress,  he 
inquired  of  the  celebrated  geometer  if  there  was 
not  some  royal  road,  could  he  not  learn  geometry 
more  easily  than  by  studying  the  Elements.  The 
learned  Greek  replied,  "There  is  no  royal  road.3 
These  royal  roads  making  every  branch  of  science 
accessible  to  the  cultivated  mind  did  not  exist  in 
the  days  of  Ptolemy  and  Euclid.  But  they  do 
exist  to-day.  These  roads  form  what  we  call 
Scientific  Philosophy. 

Scientific  philosophy  opens  a  path  through  the 
hitherto  inextricable  medley  of  natural  phenomena. 
It  throws  light  on  facts,  it  lays  bare  principles,  it 
replaces  contingent  details  by  essential  facts.  And 
thus  it  makes  science  accessible  and  communicable. 
Intellectually  it  performs  a  very  lofty  function. 

There  is  virtually  a  philosophy  of  every  science, 
v 


CONTENTS. 


BOOK  I. 

THE  FRONTIERS  OF  SCIENCE.  GENERAL  THEORIES  OF 
LIFE  AND  DEATH.  THEIR  SUCCESSIVE  TRANS- 
FORMATIONS, 

CHAP.  fAGE 

I.  EARLY  THEORIES i 

II.  ANIMISM- 5 

III.  VITALISM 15 

IV.  THE  MONISTIC  THEORY 34 

V.  THE  EMANCIPATION   OF  SCIENTIFIC  RESEARCH   FROM 

THE  YOKE  OF  PHILOSOPHICAL  DOCTRINE         .        .      42 

BOOK  II. 

THE  DOCTRINE  OF  ENERGY  AND  THE  LIVING  WORLD. 
GENERAL  IDEAS  OF  LIFE.  ALIMENTARY  LIFE. 

1.  ENERGY  IN  GENERAL 57 

IL  ENERGY  ix  BIOLOGY 97 

III.  ALIMENTARY  ENERGETICS  .     116 


BOOK  III. 
THE  CHARACTERS  COMMON  TO  LIVING  BEINGS. 

I.  DOCTRINE  OF  VITAL  UNITY 146 

II.  MORPHOLOGICAL  UNITY  OF  LIVING  BEINGS.       .        .  157 

III.  CHEMICAL  UNITY  OF  LIVING  BEINGS   .        .        .        .  173 

IV.  TWOFOLD     CONDITIONING    OF    VITAL    PHENOMENA. 

IRRITABILITY 188 

ix. 


X  CONTENTS. 

CHAP.  PAGE 

V.  THE  SPECIFIC  FORM:   ITS  ACQUISITION,  ITS  REPARA- 

TION   - 199 

VI.  NUTRITION.    FUNCTIONAL  ASSIMILATION.   FUNCTIONAL 

DISTRIBUTION.     ASSIMILATING  SYNTHESIS        .        .     209 

BOOK  IV. 
THE  LIFE  OF  MATTER. 

I.  UNIVERSAL  LIFE  (OPINIONS  OF  THE  PHILOSOPHERS 
AND  POETS).  CONTINUITY  BETWEEN  BRUTE  BODIES 
AND  LIVING  BODIES.  ORIGIN  OF  THE  PRINCIPLE  OF 

CONTINUITY 239 

II.  ORIGIN  OF  LIVING  MATTER  IN  BRUTE  MATTER  .        .     249 

III.  ORGANIZATION  AND  CHEMICAL  COMPOSITION  OF  LIVING 

MATTER  AND  BRUTE  MATTER 255 

IV.  EVOLUTION  AND  MUTABILITY  OF  LIVING  MATTER  AND 

BRUTE  MATTER  ........     259 

V.  THE  COMPOSITION  OF  THE  SPECIFIC   FORM.     LIVING 

BODIES  AND  CRYSTALS.    CICATRIZATION  .        .        .     281 
VI.  NUTRITION    IN    THE    LIVING    BEING    AND    IN    THE 

CRYSTAL 290 

VII.  GENERATION  IN  BRUTE  BODIES  AND  LIVING  BODIES. 

SPONTANEOUS  GENERATION 294 

BOOK  V. 

SENESCENCE  AND  DEATH. 
I.  THE  DIFFERENT  POINTS  OF  VIEW  FROM  WHICH  DEATH 

MAY  BE   REGARDED       . 307 

II.  CONSTITUTION  OF  THE  ORGANISMS.     PARTIAL  DEATH. 

COLLECTIVE  DEATHS 312 

III.  PHYSICAL     AND     CHEMICAL     CHARACTERISTICS     OF 

CELLULAR  DEATHS.     NECROBIOSIS     ....     321 

IV.  APPARENT  PERENNITY  OF  COMPLEX  INDIVIDUALS       .     330 
V.  IMMORTALITY    OF    THE    PROTOZOA    AND    OF    SLIGHTLY 

DIFFERENTIATED  CELLS 334 

VI.  LETHALITY  OF  THE  METAZOA  AND  OF  DIFFF.RENTIATED 

CELLS 340 

VII.  MAN.    THE  INSTINCT  OF  LIFK  AND  THE  INSTINCT  OF 

DEATH 345 

INDEX 361 


LIFE    AND    DEATH. 


BOOK  I. 

THE  FRONTIERS  OF  SCIENCE— GENERAL  THEORIES 
OF  LIFE  AND  DEATH  —  THEIR  SUCCESSIVE 
TRANSFORMATIONS. 

Chapter  I.  Early  Theories. — II.  Animism. — III.  Vitalism. — 
IV.  Monism. — V.  Emancipation  of  Scientific  Research 
from  the  Yoke  of  Philosophy. 

CHAPTER  I. 

EARLY   THEORIES. 

Animism  —  Vitalism  —  The  Physico-Chemical  Theory  —  Their 
Survival  and  Transformations. 

THE  fundamental  theories  of  science  are  but  the  ex- 
pression of  its  most  general  results.  What,  then,  is 
the  most  general  result  of  the  development  of 
physiology  or  biology — that  is  to  say,  of  that  depart- 
ment of  science  which  has  life  as  its  object?  What 
glimpse  do  we  get  of  the  fruit  of  all  our  efforts  ?  The 
answer  is  evidently  the  response  to  that  essential 
question — What  is  Life  ? 

There  are  beings  which  we  call  living  beings  ;  there 
are  bodies  which  have  never  been  alive — inanimate 
bodies  ;   and   there  are  bodies  which  are   no  longer 
i 


2  LIFE    AND    DEATH. 

alive — dead  bodies.  The  fact  that  we  use  these  terms 
implies  the  idea  of  a  common  attribute,  of  a  quid pro- 
firium,  life,  which  exists  in  the  first,  has  never  existed 
in  the  second,  and  has  ceased  to  exist  in  the  last.  Is 
this  idea  correct?  Suppose  for  a  moment  that  this 
is  so,  that  this  implicit  supposition  has  a  foundation, 
and  that  there  really  is  something  which  corresponds 
to  the  word  "life"  Must  we  then  wait  for  the  last 
days  of  physiology,  and  in  a  measure  for  its  last 
word  before  we  know  what  is  hidden  behind  this 
word,  "  life  "  ? 

Yes,  no  doubt  positive  science  should  be  precluded 
from  dealing  with  questions  of  this  kind,  which  are 
far  too  general.  It  should  be  limited  to  the  study  of 
second  causes.  But,  as  a  matter  of  fact,  scientific 
men  in  no  age  have  entirely  conformed  to  this  pro- 
visional or  definitive  antagonism.  As  the  human 
mind  cannot  rest  satisfied  with  indefinite  attempts,  or 
with  ignorance  pure  and  simple,  it  has  always  asked, 
and  even  now  asks,  from  the  spirit  of  system  the 
solution  which  science  refuses.  It  appeals  to  philo- 
sophical speculation.  Now,  philosophy,  in  order  to 
explain  life  and  death,  offers  us  hypotheses.  It  offers 
us  the  hypotheses  of  thirty,  of  a  hundred,  or  two 
thousand  years  ago.  It  offers  us  animism  ;  vitalism 
in  its  two  forms,  unitary  vitalism  or  the  doctrine  of 
vital  force,  and  dismembered  vitalism  or  the  doctrine 
of  vital  properties ;  and  finally,  materialism,  a 
mechanical  theory,  unicism  or  monism, — to  give  it 
all  its  names — i.e.,  the  physico-chemical  doctrine  of 
life.  There  are,  therefore,  at  the  present  day,  in 
biology,  representatives  of  these  three  systems  which 
have  never  agreed  on  the  explanation  of  vital 
phenomena — namely,  animists,  vitalists,  and  monists. 


EARLY  THEORIES.  3 

But  it  is  pretty  clear  that  there  must  have  been 
some  change  between  yesterday  and  to-day.  Not 
in  vain  has  general  science  and  biology  itself  made 
the  progress  which  we  know  has  been  made  since 
the  Renaissance,  and  especially  during  the  course 
of  the  nineteenth  century.  The  old  theories  have 
been  compelled  to  take  new  shape,  such  parts  as  have 
become  obsolete  have  been  cut  away,  another 
language  is  spoken — in  a  word,  the  theories  have 
become  rejuvenated.  The  neo-animists  of  our  day, 
Chauffard  in  1878,  von  Bunge  in  1889,  and  more 
recently  Rindfleisch,  do  not  hold  exactly  the  same 
views  as  Aristotle,  St.  Thomas  Aquinas,  or  Stahl. 
Contemporary  neo-vitalists,  physiologists  like  Heiden- 
hain,  chemists  like  Armand  Gautier,  or  botanists  like 
Reinke  do  not  between  1880  and  1900  hold  the  same 
views  as  Paracelsus  in  the  fifteenth  century  and  Van 
Helmont  in  the  seventeenth,  as  Barthez  and  Bordeu  at 
the  end  of  the  eighteenth,  or  as  Cuvier  and  Bichat  at 
the  beginning  of  the  nineteenth  century.  Finally,  the 
mechanicians  themselves,  whether  they  be  disciples 
of  Darwin  and  Haeckel,  as  most  biologists  of  our 
own  time,  or  disciples  of  Lavoisier,  as  most  physio- 
logists of  the  present  day,  have  passed  far  beyond  the 
ideas  of  Descartes.  They  would  reject  the  coarse 
materialism  of  the  celebrated  philosopher.  They 
would  no  longer  consider  the  living  organism  as  a 
machine,  composed  of  nothing  but  wheels,  springs, 
levers,  presses,  sieves,  pipes,  and  valves ;  or  again 
of  matrasses,  retorts,  or  alembics,  as  the  iatro- 
mechanicians  and  would-be  chemists  of  other  days 
believed. 

All  that  is  changed,  at  any  rate  in  form.    If  we  look 
back  only  thirty  or  forty  years  we  see  that  the  old 


4  LIFE    AND    DEATH. 

doctrines  have  undergone  more  or  less  profound 
modifications.  The  changes  of  form,  which  have  been 
made  necessary  by  the  acquisitions  of  contemporary 
science,  enable  us  to  appreciate  its  progress.  They 
enable  us  to  give  an  account  of  the  progress  of 
biology,  and  for  this  reason  they  deserve  to  be 
examined  with  some  attention.  It  is  into  this 
examination  that  I  ask  my  readers  to  accompany  me. 


CHAPTER    II. 

ANIMISM. 

The  Common  Characteristic  of  Animism  and  Vitalism :  the 
Human  Statue — Primitive  Animism — Stahl's  Animism — 
First  Objection  with  Reference  to  the  Relation  between 
Soul  and  Body — Second  Objection :  the  Unconscious 
Character  of  Vital  Operations — Twofold  Modality  of  the 
Soul — Continuity  of  the  Soul  and  Life. 

CHILDREN  are  taught  that  there  are  three  kingdoms 
in  Nature — the  mineral  kingdom  and  the  two  living 
kingdoms,  animal  and  vegetable.  This  is  the  whole 
of  the  sensible  world.  Then  above  all  that  is  placed 
the  world  of  the  soul.  School-boys  therefore  have 
no  doubts  on  the  doctrines  that  we  discuss  here. 
They  have  the  solution.  To  them  there  are  three 
distinct  spheres,  three  separate  worlds — matter,  life, 
and  thought. 

It  is  this  preconceived  idea  that  we  are  about  to 
examine.  Current  opinion  solves  a  priori  the  question 
of  the  fundamental  homogeneity  or  lack  of  resem- 
blance of  these  three  orders  of  phenomena — the 
phenomena  of  inanimate  nature,  of  living  nature,  and 
of  the  thinking  soul.  Animism,  vitalism,  and  monism 
are,  in  reality,  different  ways  of  looking  at  them. 
They  are  the  different  answers  to  this  question : — 
Are  vital,  psychic,  and  physico-chemical  manifesta- 
tions essentially  distinct?  Vitalists  distinguish  be- 
5 


0  LIFE    AND   DEATH. 

tween  life  and  thought,  animists  identify  them.  In 
the  opposite  camp  mechanicians,  materialists,  or 
monists  make  the  same  mistake  as  the  animists,  but 
to  that  mistake  they  add  another  :  they  assimilate  the 
forces  at  play  in  animals  and  plants  to  the  general 
forces  of  the  universe;  they  confuse  all  three — soul, 
life,  inanimate  nature. 

These  problems  belong  on  many  sides  to  meta- 
physical speculation.  They  have  been  discussed  by 
philosophers ;  they  have  been  solved  from  time  im- 
memorial in  different  ways,  for  reasons  and  by  argu- 
ments which  it  is  not  our  purpose  to  examine  here, 
and  which,  moreover,  have  not  changed.  But  on 
some  sides  they  belong  to  science,  and  must  be  tested 
in  the  light  of  its  progress.  Cuvier  and  Bichat,  for 
example,  considered  that  the  forces  in  action  in 
living  beings  were  not  only  different  from  physico- 
mechanical  forces,  but  were  utterly  opposed  to  them. 
We  now  know  that  this  antagonism  does  not  exist. 

The  preceding  doctrines,  therefore,  depend  up  to  a 
certain  point  on  experiment  and  observation.  They 
are  subject  to  the  test  of  experiment  and  observation 
in  proportion  as  the  latter  can  give  us  information  on 
the  degree  of  difference  or  analogy  presented  by 
psychic,  vital,  and  physico-chemical  facts.  Now, 
scientific  investigations  have  thrown  light  on  these 
points.  There  is  no  doubt  that  the  analogies  and 
the  resemblances  of  these  three  orders  of  manifesta- 
tions have  appeared  more  and  more  numerous  and 
striking  as  our  knowledge  has  advanced.  Hence  it  is 
that  animism  can  count  to-day  but  very  few  advocates 
in  biological  science.  Vitalism  in  its  different  forms 
counts  more  supporters,  but  the  great  majority  have 
adopted  the  physicorchemical  theory. 


ANIMISM.  7 

Both  animism  and  vitalism  separate  from  matter  a 
directing  principle  which  guides  it.  At  bottom  they 
are  mythological  theories  somewhat  similar  to  the 
paganism  of  old.  The  fable  of  Prometheus  or  the 
story  of  Pygmalion  contains  all  that  is  essential. 
An  immaterial  principle,  divine,  stolen  by  the 
Titan  from  Jupiter,  or  obtained  from  Venus  by  the 
Cypriot  sculptor,  descends  from  Olympus  and 
animates  the  form,  till  then  inert,  which  has  been 
carved  in  the  marble  or  modelled  in  the  clay.  In  a 
word,  there  is  a  human  statue.  It  receives  a  breath 
of  heavenly  fire,  a  vital  force,  a  divine  spark,  a  soul, 
and  behold!  it  is  alive.  But  this  breath  can  also 
leave  it  An  accident  happens,  a  clot  in  a  vein,  a 
grain  of  lead  in  the  brain — the  life  escapes,  and  all 
that  is  left  is  a  corpse.  A  single  instant  has  proved 
sufficient  to  destroy  its  fascination.  This  is  how  all 
men  picture  to  their  minds  the  scene  of  death.  The 
breath  escapes  ;  something  flies  away,  or  flows  away 
with  the  blood.  The  happy  genius  of  the  Greeks 
conceived  a  graceful  image  of  this,  for  they  re- 
presented the  life  or  the  soul  in  the  form  of  a  butter- 
fly (Psyche)  leaving  the  body,  an  ethereal  butterfly, 
as  it  were,  opening  its  sapphire  wings. 
j^  But  what  is  this  subtle  and  transient  guest  of  the 
human  statue,  this  passing  stranger  which  makes  of 
the  living  body  an  inhabited  house?  According  to 
the  animists  it  is  the  soul  itself,  in  the  sense  in 
which  the  word  is  understood  by  philosophers ;  the 
immortal  and  reasoning  soul  To  the  vitalists  it  is 
an  inferior,  subordinate  soul ;  a  soul,  as  it  were,  of 
secondary  majesty,  the  vital  force,  or  in  a  word,  life. 

Primitive  Animism. — Animism  is  the  oldest  and 
most  primitive  of  the  conceptions  presented  to  the 


8  LIFE    AND    DEATH. 

human  mind.  But  in  so  far  as  it  is  a  co-ordinated 
doctrine,  it  is  the  most  recent.  In  fact  it  only 
received  its  definitive  expression  in  the  eighteenth 
century,  from  Stahl,  the  philosopher-physician  and 
chemist. 

According  to  Tylor,  one  of  the  first  speculations  of 
primitive  man,  of  the  savage,  is  as  to  the  difference 
between  the  living  body  and  the  corpse.  The  former 
is  an  inhabited  house,  the  latter  is  empty.  To  such 
rudimentary  intellects  the  mysterious  inhabitant  is  a 
kind  of  double  or  duplicate  of  the  human  form.  It  is 
only  revealed  by  the  shadow  which  follows  the  body 
when  illuminated  by  the  sun,  by  the  image  of  its 
reflection  in  the  water,  by  the  echo  which  repeats  the 
voice.  It  is  only  seen  in  a  dream,  and  the  figures 
which  people  and  animate  our  dreams  are  nothing 
but  these  doubled,  impalpable  beings.  Some  savages 
believe  that  at  the  moment  of  death  the  double,  or 
the  soul,  takes  up  its  residence  in  another  body. 
Sometimes  each  individual  possesses,  not  one  of  these 
souls,  but  several.  According  to  Maspero,  the 
Egyptians  counted  at  least  five,  of  which  the 
principle,  the  ka  or  double,  would  be  the  aeriform  or 
vaporous  image  of  the  living  form.  Space  is  peopled 
by  souls  on  their  travels,  which  leave  one  set  of  bodies 
to  occupy  another  set.  After  having  been  the  cause 
of  life  in  the  bodies  which  they  animated,  they 
react  from  without  on  other  beings,  and  are  the 
cause  of  all  sorts  of  unexpected  events.  They  are 
benevolent  or  malevolent  spirits. 

Analogy  inevitably  leads  simple  minds  to  extend 
the  same  ideas  to  animals  and  plants  ;  in  a  word,  to 
attribute  souls  to  everything  alive,  souls  more  or  less 
nomadic,  wandering,  or  interchangeable,  as  is  taught 


AXIMISM.  9 

in  the  doctrine  of  metempsychosis.  Mons.  L.  Errera 
points  out  that  this  primitive,  co-ordinated,  hier- 
archized  doctrine — meet  subject  for  the  poet's  art — is 
the  basis  of  all  ancient  mythologies. 

TJie  Animism  of  StaJd. — Modern  animism  was 
much  more  narrow  in  scope  It  was  a  medical  theory — 
i.e.  almost  exclusive  to  man.  Stahl  had  adopted  it 
in  a  kind  of  reaction  against  the  exaggerations  of  the 
mechanical  school  of  his  time.  According  to  him,  the 
life  of  the  body  is  due  to  the  intelligent  and  reason- 
ing soul.  It  governs  the  corporeal  substance  and 
directs  it  towards  an  assigned  end.  The  organs  are 
its  instruments.  It  acts  on  them  directly,  without 
intermediaries.  It  makes  the  heart  beat,  the  muscles 
contract,  the  glands  secrete,  and  all  the  organs  per- 
form their  functions.  Nay  more,  it  is  itself  the 
architectonic  soul,  which  has  constructed  and  which 
maintains  the  body  which  it  rules.  It  is  the  metis 
agitat  molem  of  Virgil. 

It  is  remarkable  that  these  ideas,  so  excessively 
and  exaggeratedly  spiritualistic,  should  have  been 
brought  forward  by  a  chemist  and  a  physician,  while 
ideas  completely  opposed  to  these  were  admitted  by 
philosophers  like  Descartes  and  Leibniz,  who  were 
decided  believers  in  the  spirituality  of  the  soul.  Stahl 
had  been  Professor  of  Medicine  at  the  University  of 
Halle,  physician  to  the  Duke  of  Saxe- Weimar,  and 
later  to  the  King  of  Prussia.  He  left  an  important 
medical  and  chemical  work,  both  theoretical  and 
practical.  He  is  the  author  of  the  celebrated  theory 
of  phlogiston,  which  held  its  ground  in  chemistry  up 
to  the  time  of  Lavoisier.  He  died  about  1734. 

Animism  survived  him  for  some  time,  maintained 
by  the  zeal  of  a  few  faithful  disciples.  But  after  the 


IO  LIFE    AND    DEATH. 

witty  mockery  of  Bordeu,1  in  1742,  it  began  to  decay. 
We  must,  however,  point  out  that  an  attempt  to  revive 
this  theory  was  made  in  1878  by  a  well-known  doctor 
of  the  last  generation,  E.  Chauffard.  While  preserving 
the  essential  features  of  the  theory,  this  learned 
physician  proposed  to  bring  it  into  harmony  with 
modern  science,  and  to  free  it  from  all  the  reproaches 
which  had  been  levelled  at  it. 

The  Animism  of  E,  Chauffard. — These  reproaches 
were  numerous.  The  most  serious  is  of  a  philosophic 
nature.  It  rises  from  the  difficulty  of  conceiving  a 
direct  and  immediate  action  of  the  soul,  considered  as 
a  spiritual  principle,  upon  the  matter  of  the  body. 
There  is  such  an  abyss — hewn  by  the  philosophic 
mind  itself — between  soul  and  body,  that  it  is  im- 
possible to  imagine  any  relation  between  them.  We 
can  only  get  a  glimpse  of  how  the  soul  might  become 
an  instrument  of  action. 

This  was  the  problem  which  sorely  tried  the  genius 
©f  Leibniz.  Descartes,  in  earlier  days,  attacked  it 
vigorously,  like  an  Alexander  cutting  the  Gordian 
knot  He  separated  the  soul  from  the  body,  and 
made  of  the  latter  a  pure  machine  in  the  government 
of  which  the  soul  had  no  part.  He  attributed  all  the 
known  manifestations  of  vital  activity  to  inanimate 
forces.  Leibniz,  also,  was  compelled  to  reject  all 
action,  all  contact,  all  direct  relation,  every  real  bond 
between  soul  and  body,  and  to  imagine  between  them 

1  In  a  thesis  presented  in  1742  at  Montpellier,  Bordeu,  then 
only  twenty  years  of  age,  made  game  of  the  tasks  imposed  by 
animists  on  the  Soul,  "which  has  to  moisten  the  lips  when 
required;"  or,  "whose  anger  produces  the  symptoms  of  certain 
diseases;"  or  again,  "which  is  prevented  by  the  consequences 
of  original  sin  from  guiding  and  directing  the  body." 


II 

a  purely  metaphysical  relation — pre-established  har- 
mony:— uSoui  and  body  agree  in  virtue  of  this 
harmony,  the  harmony  pre-established  since  the 
creation,  and  in  no  way  by  a  mutual,  actual,  physical 
influence.  Everything  that  takes  place  in  the  soul 
takes  place  as  if  there  were  no  body,  and  so  every- 
thing takes  place  in  the  body  as  if  there  were  no 
soul"  At  this  point  we  almost  reach  a  scientific 
materialism.  It  is  easy  for  the  materialist  to  break 
this  frail  tie  of  pre-established  harmony  which  so 
loosely  unites  body  and  soul,  and  to  exhibit  the 
organism  as  under  the  sole  control  of  universal 
mechanics  and  physics. 

Thus  the  weak  point  of  Stahl's  animism  was  the 
supposition  of  a  direct  action  exercised  on  the  organ- 
ism by  a  distinct,  heterogeneous,  spiritual  principle. 

ChaufTard  has  endeavoured  to  avoid  this  pitfalL  In 
conformity  with  modern  ideas,  he  has  brought  together 
what  the  ancient  philosophers  and  Stahl  himself 
separated — the  activity  of  matter  and  the  activity  of 
the  soul  "Thought,  action,  function,  are  embraced 
in  an  indissoluble  union."  This  is  the  classical  bat 
not  very  lucid  theory  which  has  been  so  often  re- 
produced— Hvmo  foetus  est  anima  -rirtns — which 
Bossuet  has  expressed  in  the  celebrated  formula: 
"Soul  and  body  form  a  natural  whole." 

A  second  objection  raised  against  animism  is  that 
the  soul  acts  consciously,  with  reflection,  and  with 
volition,  and  that  its  essential  attributes  are  not  found 
in  most  physiological  phenomena,  which,  on  the  con- 
trary are  automatic,  involuntary,  and  unconscious. 
The  contradictory  nature  of  these  characteristics  has 
obliged  vitalists  to  conceive  of  a  vital  principle 
distinct  from  thought  Chaufiard,  agreeing  here  with 


12  LIFE    AND    DEATH. 

Boullier,  Tissot,  and  Stahl  himself,  does  not  accept 
this  distinction ;  he  refuses  to  shatter  the  unity  of  the 
vivifying  and  thinking  principle.  He  prefers  to  at- 
tribute to  the  soul  two  modes  of  action  :  the  one 
which  is  exercised  on  the  acts  of  thought,  and  hence 
it  proceeds  consciously,  with  reflection,  and  with 
volition ;  the  other  exercising  control  over  the  physio- 
logical phenomena  which  it  governs,  "  by  unconscious 
impressions,  and  by  instinctive  determinations,  obeying 
primordial  laws."  This  soul  is  hardly  in  keeping  with 
his  definition  of  a  conscious,  reflecting,  and  voluntary 
principle;  it  is  a  new  soul,  a  somatic  soul,  singularly 
akin  to  that  racJiidian  soul  which,  according  to 
Pfliiger,  a  well-known  German  physiologist,  resides 
in  each  segment  of  the  spinal  marrow,  and  is  respon- 
sible for  reflex  movements. 

Twofold  Modality  of  the  Soul.  —  This  twofold 
modality  of  the  soul,  this  duality  admitted  by  Stahl 
and  his  disciples,  was  repugnant  to  many  thinkers, 
and  it  is  this  repugnance  that  gave  rise  to  the  vitalistic 
school.  It  appeared  to  them  to  be  a  heresy  tainted 
by  materialism — and  so  it  was.  In  this  lay  the 
strength  and  the  weakness  of  animism.  It  admits 
of  a  unique  animating  principle  for  all  the  manifes- 
tations of  the  living  being,  for  the  higher  facts  in  the 
realm  of  thought,  and  for  the  lower  facts  connected 
with  the  body.  It  throws  down  the  barriers  which 
separate  them.  It  fills  up  the  gap  between  the 
different  forms  of  human  activity,  and  assimilates 
them  the  one  to  the  other. 

Now  this  is  precisely  what  materialism  does.  It, 
too,  reduces  to  a  single  order  the  psychical  and  physi- 
ological phenomena,  between  which  it  no  longer 
recognizes  anything  but  a  difference  of  degree, 


ANIMISM.  13 

thought  being  only  a  maximum  of  the  vital  move- 
ment, or  life  a  minimum  of  thought.  In  truth,  the 
aims  of  the  two  schools  are  diametrically  opposed ; 
the  one  claims  to  raise  corporeal  activity  to  the 
dignity  of  thinking  activity,  and  to  spiritualize  the 
vital  fact ;  the  other  lowers  the  former  to  the  level  of 
the  latter  and  materializes  the  psychic  fact.  But, 
though  the  intentions  are  different,  the  result  is 
identical.  Spiritualistic  monism  inclines  towards 
materialistic  monism.  One  step  more,  and  the  soul, 
confused  with  life,  will  be  confused  with  physical 
forces. 

On  the  other  hand,  twofold  modality  has  this 
advantage,  that  it  escapes  the  objection  drawn  from 
the  existence  of  so  many  living  beings  to  which  a. 
thinking  soul  cannot  be  attributed ;  an  anencephalous 
foetus,  the  young  of  the  higher  animals,  the  lower 
animals  and  plants,  living  without  thought,  or  with  a 
minimum  of  real,  conscious  thought  The  advocate 
of  animism  replies  that  this  physiological  activity  is 
still  a  soul,  but  one  which  is  barely  aware  of  its 
existence — a  gleam  of  consciousness.  In  this  theory, 
the  knowledge  of  self,  the  consciousness,  is  of  all 
degrees.  On  the  other  hand,  in  the  eyes  of  the 
vitalist,  it  is  an  absolute  fact  which  allows  of  no 
attenuation,  of  no  middle  course  between  the  being 
and  the  non-being. 

It  is  this  conception  of  the  continuity  of  the  soul  and 
life,  it  is  the  affirmation  of  a  possible  lowering  of  the 
complete  consciousness  down  to  a  mere  gleam  of  know- 
ledge, and  finally  down  to  unconscious  vital  activity, 
which  saved  animism  from  complete  shipwreck.  That 
is  why  this  ancient  doctrine  finds,  even  in  the  present 
day,  a  few  rare  supporters.  An  able  German  scientist, 


14  LIFE    AND    DEATH. 

G.  von  Bunge,  well  known  for  his  researches  in  physio- 
logical chemistry,  professes  animistic  views  in  a  work 
which  appeared  in  1889.  He  attributes  to  organized 
beings  a  guiding  principle,  a  kind  of  vital  soul.  A 
distinguished  naturalist,  Rindfleisch,  of  Liibeck,  has 
likewise  taken  his  place  among  the  advocates  of  what 
we  may  call  neo-animism. 


CHAPTER    III. 
VITALISM. 

ks  Extreme  Forms  —  Early  Vitalism,  and  Modern  Neo-vitalism 
—Advantage  of  distinguishing  between  Soul  and  Life  — 
$  i.  The  Vitalism  of  Barthez—  Its  Extension—  The  Seat  of 
the  Vital  Principle—  The  Vital  Knot—  The  Vital  Tripod- 
Decentralisation  of  the  Vital  Principle—  §  2.  The  Doctrine 
of  Vital  Properties—  Galen,  Van  Helmont,  Xavier  Bichat, 
and  Cuvier  —  Vital  and  Physical  Properties  antagonistic  — 
§  3.  Scientific  Neo-vitalism—  Heidenhain—  §  4.  Philo- 
sophical Neo-vitalism  —  Reinke. 


Extreme  Forms:  Early  Vitalism  and  Modern 
vitalism.  —  Contemporary  neo-vitalism  has  weakened 
primitive  vitalism  in  some  important  points.  The 
latter  made  of  the  vital  fact  something  quite  specific, 
irreducible  either  to  the  phenomena  of  general  physics 
or  to  those  of  thought.  It  absolutely  isolated  life, 
separating  it  above  from  the  soul,  and  below  from  in- 
animate matter.  This  sequestration  is  nowadays 
much  less  rigorous.  On  the  psychical  side  the  barrier 
remains,  but  it  is  lowered  on  the  material  side.  The 
neo-vitalists  of  to-day  recognize  that  the  laws  of 
physics  and  chemistry  are  observed  within,  as  well  as 
without,  the  living  body;  the  same  natural  forces' 
intervene  in  both,  only  they  are  "otherwise  directed." 

The  vital  principle  of  early  times  was  a  kind  of 
anthromorphic,   pagan    divinity.      To  Aristotle,  this 
force,  the  anima,  the  Psyche,  worked,  so  to  speak,  with 
15 


l6  LIFE    AND    DEATH. 

human  hands.  According  to  the  well-known  ex- 
pression, its  situation  in  the  human  body  corresponds 
to  that  of  a  pilot  on  a  vessel,  or  to  that  of  a  sculptor 
or  his  assistant  before  the  marble  or  clay.  And,  in 
fact,  we  have  no  other  clear  image  of  a  cause  external 
to  the  object.  (We  have  no  other  representation  of  a 
force  external  to  matter  than  that  which  is  offered  by 
the  craftsman  making  an  object,  or  in  general  by  the 
human  being  with  his  activity,  free,  or  supposed  to  be 
free,  and  directed  towards  an  end  to  be  realized./ 

Personifications  of  this  kind,  the  mythological 
entities,  the  imaginary  beings,  the  ontological  fictions, 
which  ever  filled  the  stage  in  the  mind  of  our  pre- 
decessors, have  definitely  disappeared  ;  no  longer  have 
they  a  place  in  the  scientific  explanations  of  our  time. 
The  neo-vitalists  replace  them  by  the  idea  of  direction, 
which  is  another  form  of  the  same  idea  of  finality. 
The  series  of  second  causes  in  the  living  being  seems 
to  be  regulated  in  conformity  with  a  plan,  and  directed 
with  a  view  to  carrying  it  out.  The  tendency  which 
exists  in  every  being  to  carry  out  this  plan, — that  is  to 
say,  the  tendency  towards  its  end, — gives  the  impulse 
that  is  necessary  to  carry  it  out.  Neo-vitalists  claim 
that  vital  force  directs  the  phenomena  which  it  does  not 
produce,  and  which  are  in  reality  carried  out  by  the 
general  forces  of  physics  and  chemistry. 

Thus,  the  directing  impulse,  considered  as  really 
active,  is  the  last  concession  of  modern  vitalism.  If 
we  go  further,  and  if  we  refuse  to  the  directing  idea 
executive  power  and  efficient  activity,  the  vital 
principle  is  weakened,  and  we  abandon  the  doctrine. 
We  can  no  longer  invoke  it.  We  cease  to  be  vitalists 
if  the  part  played  by  the  vital  principle  is  thus  far 
restricted.  At  first  it  was  both  the  author  of  the 


VITALISM.  17 

plan  and  the  universal  architect  of  the  organic  edifice  ; 
it  is  now  only  the  architect  directing  his  workmen, 
and  they  are  physical  and  chemical  agents.  It  is  now 
reduced  to  the  plan  of  the  work,  and  even  this  plan 
has  no  objective  existence;  it  is  now  only  an  idea. 
It  has  only  a  shadow  of  reality.  To  this  it  has  been 
reduced  by  certain  biologists.  For  this  we  may  thank 
Claude  Bernard;  and  he  has  thereby  placed  himself 
outside  and  beyond  the  weakest  form  of  vitalism.  He 
did  not  consider  the  idea  of  direction  as  a  real 
principle.  The  connection  of  phenomena,  their 
harmony,  their  conformity  to  a  plan  grasped  by  the 
intellect,  their  fitness  for  a  purpose  known  to  the 
intellect,  are  to  him  but  a  mental  necessity,  a  meta- 
physical concept.  The  plan  which  is  carried  out  has 
only  a  subjective  existence;  the  directing  force  has  no 
efficient  virtue,  no  executive  power;  it  does  not 
emerge  from  the  intellectual  domain  in  which  it  took 
its  rise,  and  does  not  "  react  on  the  phenomena  which 
enabled  the  mind  to  create  it." 

It  is  between  these  two  extreme  incarnations  of  the 
vital  principle,  on  the  one  hand  an  executive  agent,  on 
the  other  a  simple  directing  plan,  that  the  motley  pro- 
cession of  vitalist  doctrines  passes  on  its  way.  At  the 
point  of  departure  we  have  a  vital  force,  personified, 
acting,  as  we  have  stated,  as  if  with  human  hands 
fashioning  obedient  matter;  this  is  the  pure  and 
primitive  form  of  the  theory.  At  the  other  extreme  we 
have  a  vital  force  which  is  now  only  a  directing  idea, 
without  objective  existence,  and  without  an  executive 
role;  a  mere  concept  by  which  the  mind  gathers 
together  and  conceives  of  a  succession  of  physico- 
chemical  phenomena.  On  this  side  we  are  brought 
into  touch  with  monism. 


l8  LIFE    AND    DEATH. 

The  Reasons  given  by  the  Vitalists  for  distinguishing 
Soul  from  Life. — It  is,  in  particular,  on  the  opposite 
side,  in  the  psychical  world,  that  the  early  vitalists  pro- 
fessed to  entrench  themselves.  We  have  just  seen  that 
their  doctrines  were  not  so  subtle  as  those  of  to-day ; 
the  vital  principle  to  them  was  a  real  agent,  and  not  an 
ideal  plan  in  the  process  of  being  carried  out.  But 
they  distinguished  this  spiritual  principle  from  another 
co-existent  with  it  in  superior  living  beings — at  any 
rate,  in  man :  the  thinking  soul.  They  boldly  dis- 
tinguished between  them,  because  the  activity  of  the 
one  is  manifested  by  knowledge  and  volition,  while 
on  the  contrary,  the  manifestations  of  the  other  for 
the  most  part  escape  both  consciousness  and  volition. 

In  fact,  we  know  nothing  of  what  goes  on  in  the 
normal  state  of  our  organs.  Their  perfect  performance 
of  their  functions  is  translated  to  us  solely  by  an 
obscure  feeling  of  comfort.  We  do  not  feel  the  beat- 
ing of  the  heart,  the  periodic  dilations  of  the  arteries, 
the  movements  of  the  lungs  or  intestine,  the  glands  at 
their  work  of  secretion,  or  the  thousand  reflex  mani- 
festations of  our  nervous  system.  The  soul,  which  is 
conscious  of  itself,  is  nevertheless  ignorant  of  all  this 
vital  movement,  and  is  therefore  external  to  it. 

This  is  the  view  of  all  the  philosophers  of  antiquity. 
Pythag.oras  distinguished  the  real  soul,  the  thinking 
soul,  the  Nous,  the  intelligent  and  immortal  principle, 
characterized  by  the  attributes  of  consciousness  and 
volition,  from  the  vital  principle,  the  Psyche,  which 
gives  breath  and  animation  to  the  body,  and  which  is 
a  soul  of  secondary  majesty,  active,  transient,  and 
mortal.  Aristotle  did  the  same.  On  the  one  side  he 
placed  the  soul  properly  so  called,  the  Nous  or 
intellect — that  is  to  say,  the  understanding  with  its 


VITALISM.  19 

rational  intelligence ;  on  the  other  side  was  the 
directing  principle  of  life,  the  irrational  and  vegeta- 
tive Psyche. 

This  distinction  agrees  with  the  fact  of  the  diffusion 
of  life.  Life  does  not  belong  to  the  superior  animals 
alone,  and  to  the  man  in  whom  we  can  recognize  a 
reasoning  soul.  It  is  extended  to  the  vast  multitude 
of  humbler  beings  to  which  such  lofty  faculties  cannot 
be  attributed,  the  invertebrates,  microscopic  animals, 
and  plants.  The  advantage  is  compensated  for  by 
the  inconvenience  of  breaking  down  all  continuity 
between  the  soul  and  life;  a  continuity  which  is  the 
principle  of  the  two  other  doctrines,  animism  and 
monism,  and  which  is,  we  may  say,  the  very  aim  and 
the  unquestionable  tendency  of  science. 

As  for  classical  philosophy,  it  satisfies  the  necessity 
of  establishing  the  unity  of  the  living  being, — />.,  of 
bringing  into  harmony  soul  and  body, — but  in  a 
.manner  which  we  need  not  here  discuss.  It  at- 
tributes to  the  soul  several  modalities,  several  distinct 
powers:  powers  of  the  vegetative  life,  powers  of  the 
sensitive  life,  and  powers  of  the  intellectual  life.  And 
this  other  solution  of  the  problem  would  be,  in  the 
opinion  of  M.  Gardair,  in  complete  agreement  with 
the  doctrines  of  St.  Thomas  Aquinas. 


§  i.  THE  VITALISM  OF  BARTHEZ  :  ITS  EXTENSION. 

Vitalism  reached  its  most  perfect  expression  in  the 
second  half  of  the  eighteenth  century  in  the  hands  of 
the  representatives  of  the  Montpellier  school — Bordeu, 
Grimaud,  and  Barthez.  The  last,  in  particular, 
contributed  to  the  prevalence  of  the  doctrine  in 


20  LIFE    AND    DEATH. 

medical  circles.  A  man  of  profound  erudition,  a 
collaborates  with  d'Alembert  in  the  Encyclopedia, 
he  exercised  quite  a  preponderant  influence  on  the 
medicine  of  his  day.  Stationed  at  Paris  during  part 
of  his  career,  physician  to  the  King  and  the  Duke  of 
Orleans,  we  may  say  that  he  supported  his  theories  by 
every  imaginable  influence  which  might  contribute  to 
their  success.  In  consequence  of  this,  the  medical 
schools  taught  that  vital  phenomena  are  the  immediate 
effects  of  a  force  which  has  no  analogues  outside  the 
living  body.  This  conception  reigned  unchallenged 
up  to  the  days  of  Bichat 

After  Bichat,  the  vitalism  of  Barthez,  more  or  less 
modified  by  the  ideas  of  the  celebrated  anatomist, 
continued  to  hold  its  own  in  all  the  schools  of 
Europe  until  about  the  middle  of  the  nineteenth 
century.  Johannes  Mtiller,  the  founder  of  physiology 
in  Germany,  admitted,  about  1833,  the  existence  of  a 
unique  vital  force  "aware  of  all  the  secrets  of  the 
forces  of  physics  and  chemistry,  but  continually  in 
conflict  with  them,  as  the  supreme  cause  and  regulator 
of  all  phenomena."  When  death  came,  this  principle 
disappeared  and  left  no  trace  behind.  One  of  the 
founders  of  biological  chemistry,  Justus  Liebig,  who 
died  in  1873,  shared  these  ideas.  The  celebrated 
botanist,  Candolle,  who  lived  up  to  1893,  taught  at 
the  beginning  of  his  career  that  the  vital  force  was  one 
of  the  four  forces  ruling  in  nature,  the  other  three 
being — attraction,  affinity,  and  intellectual  force. 
Flourens,  in  France,  made  the  vital  principle  one  of 
the  five  properties  of  forces  residing  in  the  nervous 
system.  Another  contemporary,  Dressel,  in  1883, 
endeavoured  to  bring  back  into  fashion  this  rather 
primitive,  monistic,  and  efficient  vitalism. 


VITALISM.  21 

T/K  Scat  of  the  Vital  Principle.— Meanwhile, 
another  question  was  asked  with  reference  to  this 
vital  principle.  It  was  a  question  of  ascertaining  its 
seat:  or,  in  other  words,  of  finding  its  place  in  the 
organism.  Is  it  spread  throughout  the  organism,  or  is 
it  situated  in  some  particular  spot  from  which  it  acts 
upon  every  part  of  the  body?  Van  Helmont,  a  cele- 
brated scientist  at  the  end  of  the  sixteenth  century, 
who  was  both  physician  and  alchemist,  gave  the  first 
and  rather  quaint  solution  of  this  difficult}'.  The  vital 
principle,  according  to  him,  was  situated  in  the 
stomach,  or  rather  in  the  opening  of  the  pylorus.  It 
was  the  concierge,  so  to  speak,  of  the  stomach.  The 
Hebrew  idea  was  more  reasonable.  The  life  was 
connected  with  the  blood,  and  was  circulated  with  it 
by  means  of  all  the  veins  of  the  organism.  It  escaped 
from  a  wound  at  the  same  time  as  the  liquid  blood. 
It  is  clear  that  in  this  belief  we  see  why  the  Jews  were 
forbidden  to  eat  meat  which  had  not  been  bled. 

T/u  Vital  Knot. — In  1748  a  doctor  named  Lorry 
found  that  a  very  small  wound  in  a  certain  region  of 
the  spinal  marrow  brought  on  sudden  death.  The 
position  of  this  remarkable  point  was  ascertained  in 
1812  by  Legallois,  and  more  accurately  still  by 
Flourens  in  1827.  It  is  situated  in  the  rachidian 
bulb,  at  the  level  of  the  junction  of  the  neck  and  the 
head;  or  more  precisely,  on  the  floor  of  the  fourth 
ventricle,  near  the  origin  of  the  eighth  pair  of  cranial 
nerves.  This  is  what  was  called  the  vital  knot. 
Upon  the  integrity  of  this  spot,  which  is  no  bigger 
than  the  head  of  a  pin,  depends  the  life  of  the  animal. 
Those  who  believed  in  a  localisation  of  the  vital 
principle  thought  that  they  had  found  the  seat 
desired ;  but  for  that  to  be  so  the  destruction  of  this 


22  LIFE    AND    DEATH. 

spot  must  be  irremediable,  and  must  necessarily  cause 
death.  But  if  the  vital  knot  be  destroyed,  and 
respiration  ^  be  artificially  induced  by  means  of  a 
bellows,  the  animal  resists:  it  continues  to  live.  It  is 
only  the  nervous  stimulating  mechanism  of  the 
respiratory  movements  which  has  been  attacked  in 
one  of  its  essential  parts. 

Life,  therefore,  resides  no  more  in  this  point  than  it 
does  in  the  blood  or  in  the  stomach.  Later  experi- 
ment has  shown  that  it  resides  everywhere,  that  each 
organ  enjoys  an  independent  life.  Each  part  of  the 
body  is,  to  use  Bordeu's  strong  expression,  "an  animal 
in  an  animal" ';  or  to  adopt  the  phrase  due  to  Bichat, 
*' a  particular  machine  witliin  tJie  general  machine" 

The  Vital  Tripod. — What  then  is  life,  or,  in  other 
words,  what  is  the  biological  activity  of  the  individual, 
of  the  animal,  of  man  ?  It  is  clearly  the  sum  total,  or 
rather,  the  harmony  of  these  partial  lives  of  the 
different  organs.  But  in  this  harmony  it  seems  that 
there  are  certain  instruments  which  dominate  and 
sustain  the  others.  There  are  some  whose  integrity 
is  more  necessary  to  the  preservation  of  existence  and 
health,  and  of  which  any  lesion  makes  death  more 
inevitable.  They  are  the  lungs,  the  heart,  and  the 
brain.  Death  always  ensues,  said  the  early  doctors,  if 
any  one  of  these  three  organs  be  injured.  Life 
depends,  therefore,  on  them,  as  if  upon  a  three-legged 
support.  Hence  the  idea  of  the  vital  tripod.  It  is  no 
longer  a  single  seat  for  the  vital  principle,  but  a  kind 
of  throne  on  three-supports.  Life  is  decentralized. 

This  was  only  the  first  step,  very  soon  followed  by 
many  others,  in  the  direction  of  vital  decentralization. 
(Experiment  showed,  in  fact,  that  every  organ  separated 
Ifrom  the  body  will  continue  to  live  if  provided  with 


VITALISM.  23 

the  proper  conditions^  And  here,  it  is  not  only  a 
question  of  inferior  beings;  of  plants  that  are  pro- 
pagated by  slips;  of  the  hjdra  which  Trembley  cut 
into  pieces,  each  of  which  generated  a  complete  hydra ; 
of  the  nais  which  C  Bonnet  cut  up  into  sections,  each 
of  which  reconstituted  a  complete  annelid.  There  is 
no^  exception  to  the.jule. 

Decentralization  of  the  Vital  Principle.— The  result 
is  the  same  in  the  higher  vertebrates,  only  the  experi- 
ment is  much  more  difficult.  At  the  Physiological 
Congress  of  Turin  in  1901,  Locke  showed  the  heart  of 
a  hare,  extracted  from  the  body  of  the  animal,  and 
beating  for  hours  as  energetically  and  as  regularly  as 
if  it  were  in  its  place.  He  suspended  it  in  the  air  of 
a  room  at  the  normal  temperature,  the  sole  condition 
being  that  it  was  irrigated  with  a  liquid  composed  of 
certain  constituents.  The  animal  had  been  dead  some 
time.  More  recently  Kuliabko  has  shown  in  the  same 
way  the  heart  of  a  man  still  beating,  although  the 
man  had  been  dead  some  eighteen  hours.  The  same 
experiment  is  repeated  in  any  physiological  labora- 
tory, in  a  much  easier  manner,  with  the  heart  of  a 
tortoise  This  organ,  extracted  from  the  body,  fitted 
up  with  rubber  tubes  to  represent  its  arteries  and 
veins,  and  filled  with  the  defibrinated  blood  of  a  horse 
or  an  ox  taken  from  the  slaughter-house,  works  for 
hours  and  days  pumping  the  liquid  blood  into  its 
rubber  aorta,  just  as  if  it  were  pumping  it  into  the 
living  aorta. 

But  it  is  unnecessary  to  multiply  examples.  Every 
organ  can  be  made  to  live  for  a  longer  or  shorter 
period  even  though  removed  from  its  natural  position ; 
muscles,  nerves,  glands,  and  even  the  brain  itself. 
Each  organ,  each  tissue  therefore  enjoys  an  inde- 

3 


24  LIFE    AND    DEATH. 

pendent  existence ;  it  lives  and  works  for  itself. 
No  doubt  it  shares  in  the  activity  of  the  whole,  but 
it  may  be  separated  therefrom  without  being  thereby 
placed  in  the  category  of  dead  substances.  For  each 
aliquot  part  of  the  organism  there  is  a  partial  life  and 
a  partial  death. 

This  decentralization  of  the  vital  activity  is  finally 
extended  in  complex  beings  from  the  organs  to  the 
tissues,  and  from  the  tissues  to  the  anatomical 
elements — the  cells.  The  idea  of  decentralization 
has  given  birth  to  the  second  form  of  vitalism,  a 
softened  down  and  weakened  form — namely,  pluri- 
vitalism,  or  the  theory  of  vital  properties. 


§  2.  THE  THEORY  OF  VITAL  PROPERTIES. 

The  advocates  of  the  theory  of  vital  properties  have 
cut  up  into  fragments  the  monistic  and  indivisible 
guiding  principle  of  Bordeu  and  Barthez.  They  have 
given  it  new  currency — pluri-vitalism.  This  theory 
maintains  the  existence  of  spiritual  powers  of  a  lower 
order,  which  control  phenomena  more  intimately  than 
the  vital  principle  did.  These  powers,  less  lofty  in 
their  dignity  than  the  rational  soul  of  the  animists,  or 
the  soul  of  secondary  majesty  of  the  Unitarian 
vitalists,  are  eventually  incorporated  in  the  living 
matter  of  which  they  will  then  be  no  longer  more 
than  the  properties.  Brought  into  closer  connection 
therefore  with  the  sensible  world,  they  will  be  more 
in  harmony  with  the  spirit  of  research  and  with 
scientific  progress. 

The  defect  of  the  earlier  conceptions,  their  common 
illusion,  rose  from  their  seeking  the  cause  outside  the 


VITALISM.  25 

object,  from  their  demanding  an  explanation  of  vital 
phenomena  from  a  principle  external  to  living, 
immaterial,  and  unsubstantial  matter.  Here  this 
defect  is  less  marked.  The  pluri-vitalists  will  in  turn 
appeal  to  the  vital  properties  as  modes  of  activity, 
inherent  in  the  living  substance  in  which  and  by  which 
they  are  manifested,  and  derived  from  the  arrangement 
of  the  molecules  of  this  substance — that  is  to  say,  from 
its  organization.  This  is  almost  the  conception  of 
the  present  day. 

But  this  progress  will  only  be  realized  at  the  end  of 
the  evolution  of  the  pluri-vitalist  theory.  At  the  outset 
this  theory  seems  an  exaggeration  of  its  predecessor, 
and  a  still  more  exaggerated  form  of  the  mythological 
paganism  with  which  it  was  reproached.  The  archeus, 
the  bias,  the  properties,  the  spirits — all  have  at  first 
the  effect  of  the  genii  or  of  the  gods  imagined  by  the 
ancients  to  preside  over  natural  phenomena,  of 
Neptune  stirring  up  the  waters  of  the  sea,  and  of 
Eolus  unchaining  the  winds.  These  divinities  of  the 
ancient  world,  the  nymphs,  the  dryads,  and  the  sylvan 
gods,  seem  to  be  transported  to  the  Middle  Ages,  to 
that  age  of  argument,  that  philosophical  period  of  the 
history  of  humanity,  and  there  metamorphosed  into 
occult  causes,  immaterial  powers,  and  personified 
forces. 

Galen. — The  first  of  the  pluri-vitalists  was  Galen, 
the  physician  of  Marcus  Aurelius,  the  celebrated 
author  of  an  Encyclopaedia  of  which  the  greater  part 
has  been  lost,  and  of  which  the  one  book  preserved 
held  its  own  as  the  anatomical  oracle  and  breviary 
throughout  the  Middle  Ages.  According  to  Galen 
the  human  machine  is  guided  by  three  kinds  of 
spirits:  animal  spirits,  presiding  over  the  activity  of 


26  LIFE   AND   DEATH. 

the  nervous  system;  vital  spirits  governing  most  of 
the  other  functions;  and  finally,  natural  spirits 
regulating  the  liver  and  susceptible  of  incorporation 
in  the  blood.  In  the  sixteenth  century,  in  the  time  of 
Paracelsus,  Galen's  spirits  became  Olympic  spirits. 
They  still  presided  over  the  functional  activity  of  the 
organs,  the  liver,  heart,  and  brain,  but  they  also 
existed  in  all  the  bodies  of  nature. 

Van  Helmont. — Finally,  the  theory  was  laid  down 
by  Van  Helmont,  physician,  chemist,  experimentalist, 
and  philosopher,  endowed  with  a  rare' and  penetrating 
intellect.  Here  we  find  many  profound  truths  com- 
bined with  fantastic  dreams.  Refusing  to  admit  the 
direct  action  of  an  immaterial  agent,  such  as  the  soul, 
on  inert  matter,  on  the  body,  he  filled  up  the  abyss 
which  separated  them  by  creating  a  whole  hierarchy 
of  immaterial  principles  which  played  the  part  of 
mediators  and  executive  agents.  At  the  head  of  this 
hierarchy  was  placed  the  thinking  and  immortal  soul ; 
below  was  the  sensitive  and  mortal  soul,  having  for  its 
minister  the  principal  archeus,  the  aura  vitalis,  a  kind 
of  incorporeal  agent,  which  is  remarkably  like  the 
vital  principle,  and  which  had  its  seat  at  the  orifice  of 
the  stomach.  Below  again  were  the  subordinate 
agents,  the  bias,  or  vulcans  placed  in  each  organ,  and 
intelligently  directing  its  mechanism  like  skilful 
workmen. 

These  chimerical  ideas  are  not,  however,  so  far 
astray  as  the  theory  of  vital  properties.  When  we 
see  a  muscle  contract,  we  say  that  this  phenomenon 
is  due  to  a  vital  property — i.e.,  a  property  without  any 
analogue  in  the  physical  world,  namely  contractility, 
In  the  same  way  the  nerve  possesses  two  vital 
properties,  excitability  and  conductibility, \t\\\z\\  Vulpian 


VITALISM.  27 

proposed  to  blend  into  one,  calling  it  neurility.  These 
are  mere  names,  serving  as  a  kind  of  shorthand;  but 
to  those  who  believe  that  there  is  something  real  in  it, 
this  something  is  not  very  far  from  the  bias  of  Van 
Helmont  Vufcans,  hidden  in  the  muscle  or  the  nerve, 
are  here  detected  by  attraction,  there  by  the  pro- 
duction and  the  propagation  of  the  nervous  influx; 
that  is  to  say,  by  phenomena  of  which  we  as  yet 
know  no  analogues  in  the  physical  world,  but  of 
which  we  cannot  say  that  they  do  not  exist 

X.  BicJtat  and  G.  Cuvier:  Vital  and  Physical 
Properties  Antagonistic. — The  archeus  and  the  bias  of 
Van  Helmont  were  but  a  first  rough  outline  of 
vital  properties.  Xavier  Bichat,  the  founder  of  general 
anatomy,  wearied  of  all  these  incorporeal  entities,  of 
these  unsubstantial  principles  with  which  biology  was 
encumbered,  undertook  to  get  rid  of  them  by  the 
methods  of  the  physicist  and  the  chemist  The  physics 
and  the  chemistry  of  his  day  referred  phenomenal 
manifestations  to  the  properties  of  matter,  gravity, 
capillarity,  magnetism,  etc.  Bichat  did  the  same- 
He  referred  vital  manifestations  to  the  properties  of 
living  tissues,  if  not,  indeed,  of  living  matter.  Of 
these  properties  as  yet  but  very  few  were  known  : 
the  irritability  described  by  Glisson,  which  is  the 
excitability  of  current  physiology  ;  and  the  irritability 
of  Haller,  which  is  nothing  but  muscular  contrac- 
tility. Others  had  to  be  discovered. 

There  is  no  need  to  recall  the  mistake  made  by 
Bichat  and  followed  by  most  scientific  men  of  his 
time,  such  as  Cuvier  in  France,  and  J.  Miiller  in 
Germany,  for  the  story  has  been  told  by  Claude 
Bernard.  His  mistake  was  in  considering  the  vital 
properties  not  only  as  distinct  from  physical  properties 


28  LIFE   AND   DEATH. 

but  even  as  opposed  to  them.  The  one  preserve  the 
body,  the  others  tend  to  destroy  it.  They  are  always 
in  conflict.  Life  is  the  victory  of  the  one;  death  is 
the  triumph  of  the  other.  Hence  the  celebrated 
definition  given  by  Bichat:  "Life  is  the  sum  total  of 
functions  which  resist  death,"  or  the  definition  of  the 
Encyclopaedia:  "Life  is  the  contrary  of  death." 

Cuvier  has  illustrated  this  conception  by  a  graphic 
picture.  He  represents  a  young  woman  in  all  the 
health  and  strength  of  youth  suddenly  stricken  by 
death.  The  sculptural  forms  collapse  and  show  the 
angularities  of  the  bones;  the  eyes  so  lately  sparkling 
become  dull;  the  flesh  tint  gives  place  to  a  livid 
pallor;  the  graceful  suppleness  of  the  body  is  now 
rigidity, "  and  it  will  not  be  long  before  more  horrible 
changes  ensue ;  the  flesh  becomes  blue,  green,  black, 
one  part  flows  away  in  putrid  poison,  and  another 
part  evaporates  in  infectious  emanations.  Finally, 
nothing  is  left  but  saline  or  earthy  mineral  principles, 
all  the  rest  has  vanished."  Now,  according  to  Cuvier, 
what  has  happened  ? 

These  alterations  are  the  effect  of  external  agents, 
air,  humidity,  and  heat.  They  have  acted  on  the 
corpse  just  as  they  used  to  act  on  the  living  being ; 
but  before  death  their  assault  had  no  effect,  because  it 
was  repelled  by  the  vital  properties.  Now  that  life 
has  disappeared  the  assault  is  successful.  We  know 
now  that  external  agents  are  not  the  cause  of  these 
disorders.  They  are  caused  by  the  microbes  of 
putrefaction.  It  is  against  tJieni  that  the  organs  were 
struggling,  and  not  against  physical  forces. 

The  mistake  made  by  Bichat  and  Cuvier  was  in- 
excusable, even  in  their  day.  They  were  wrong  not 
to  attach  the  importance  they  deserved  to  Lavoisier's 


VITALISM.  29 

researches.  He  had  asserted,  apropos  of  animal  heat 
and  respiration,  the  identity  of  the  action  of  physical 
agents  in  the  living  body  and  in  the  external  world. 
On  the  other  hand,  Bichat,  by  a  flash  of  genius,  de- 
centralized life,  dispersing  the  vital  properties  in  the 
tissues,  or,  as  we  should  now  say,  in  the  living  matter. 
It  was  from  the  comparison  between  the  constitution 
and  the  properties  of  living  matter  and  those  of  in- 
animate matter  that  light  was  to  come. 


|  3.  SCIENTIFIC  XEO- VITALISM. 

We  can  now  understand  the  nature  of  modem 
neo-vitalism.  It  borrows  from  its  predecessor  its 
fundamental  principle — namely,  the  specificity  of  the 
vital  fact  But  this  specificity  is  no  longer  essential, 
it  is  only  formal.  The  difference  between  it  and  the 
physical  fact  grows  less  and  almost  vanishes.  It  con- 
sists of  a  diversity  of  mechanisms  or  executive  agents. 
For  example,  digestion  transforms  the  alimentary 
starch  in  the  intestines  into  sugar;  the  chemist  does 
the  same  in  his  laboratory,  only  he  employs  acids, 
while  the  organism  employs  special  agents,  ferments, 
in  this  case  a  diastase.  It  is  a  particular  form  of 
chemistry,  but  still  it  is  a  chemistry.  That  is  how 
Claude  Bernard  looked  at  it.  The  vital  fact  was  not 
fundamentally  distinguished  from  the  physico-chemi- 
cal fact,  but  only  in  form. 

This  expurgated  and  accommodated  vitalism 
(Claude  Bernard  pushed  his  concessions  so  far  as  to 
call  his  doctrine  "  physico-chemical  vitalism  ")  was  re- 
vived a  few  years  ago  by  Chr.  Bohr  and  Hetdenhain. 

Other  biologists,  instead  of  attributing  the  difference 


30  LIFE   AND   DEATH. 

between  the  phenomena  of  the  two  orders  to  the 
manner  of  their  occurrence,  seem  to  admit  the  com- 
plete identity  of  the  mechanisms.  It  is  no  longer 
then  in  itself,  individually,  that  the  vital  act  is 
particularized,  but  in  the  manner  in  which  it  is 
linked  to  others.  The  vital  order  is  a  series  of 
physico-chemical  acts  realizing  an  ideal  plan. 

Neo-vitalism  has  therefore  assumed  two  forms, 
one  the  more  scientific  and  the  other  the  more 
philosophical. 

Chr.  Bohr  and  HeidenJiain. — Its  scientific  form  was 
given  to  it  by  Chr.  Bohr,  an  able  physiologist  at 
Copenhagen,  and  by  Heidenhain,  a  professor  at 
Breslau,  who  was  one  of  the  lights  of  contemporary 
German  physiology.  The  course  of  their  researches 
led  these  two  experimentalists,  working  independ- 
ently, to  submit  to  fresh  investigation  the  ideas  of 
Lavoisier  and  those  of  Bichat,  on  the  relation  of 
physico-chemical  forces  to  the  vital  forces. 

It  was  by  no  means  a  question  of  a  general 
inquiry,  deliberately  instituted  with  the  object  of  dis- 
covering the  part  played  respectively  by  physical  and 
physiological  factors  in  the  performance  of  the  various 
functions.  Such  an  investigation  would  have  taken 
several  generations  to  complete.  No;  the  question 
had  only  come  up  incidentally.  Chr.  Bohr  had  studied 
with  the  utmost  care  the  gaseous  exchanges  which 
take  place  between  the  air  and  the  blood  in  the  lungs. 
The  gaseous  mixture  and  the  liquid  blood  are  face 
to  face ;  they  are  separated  by  thin  membrane  formed 
of  living  cells.  Will  this  membrane  behave  as  an 
inert  membrane  deprived  of  vitality,  and  therefore 
obeying  the  physical  laws  of  the  diffusion  of  gases  ? 
Well !  no.  It  does  not  so  behave.  The  most  careful 


VITALISM.  31 

measurements  of  pressures  and  of  solubilities  leave  no 
doubt  in  this  respect.  The  living  elements  of  the 
pulmonary  membrane  must  therefore  intervene  in 
order  to  disturb  the  physical  phenomenon.  Things 
happen  as  if  the  exchanged  gases  were  subjected  not 
to  a  simple  diffusion,  a  physical  fact  obeying  certain 
rules,  but  to  a  real  secretion,  a  physiological  or  vital 
phenomenon,  obeying  laws  which  are  also  fixed,  but 
different  from  the  former. 

On  the  other  hand,  Heidenhain  was  led  about  the 
same  time  to  analogous  conclusions  with  respect 
to  the  liquid  exchanges  which  take  place  within 
the  tissues,  between  the  liquids  (lymphs)  which 
bathe  the  blood-vessels  externally  and  the  blood 
which  those  vessels  contain.  The  phenomenon  is 
very  important  because  it  is  the  prologue  of  the 
actions  of  nutrition  and  assimilation.  Here  again, 
the  two  factors  of  exchange  are  brought  into  relation 
through  a  thin  wall,  the  wall  of  the  blood-vessel  The 
physical  laws  of  diffusion,  of  osmosis,  and  of  dialysis, 
enable  us  to  foretell  what  would  take  place  if  the 
vitality  of  the  elements  of  the  wall  did  not  intervene. 
Heidenhain  thought  he  observed  that  things  took 
place  otherwise.  The  passage  of  the  liquids  is  dis- 
turbed by  the  fact  that  the  cellular  elements  are  aliire. 
It  assumes  the  characteristics  of  a  physiological  act, 
and  no  longer  those  of  a  physical  act  Let  us  add 
that  the  interpretation  of  these  experiments  is  difficult, 
and  it  has  given  rise  to  controversies  which  still 
persist. 

These  two  examples,  around  which  others  might  be 
grouped,  have  led  certain  physiologists  to  diminish  the 
importance  of  the  physical  factors  in  the  functional 
activity  of  the  living  being  to  the  advantage  of  the 


32  LIFE   AND   DEATH. 

physiological  factors.  It  would  therefore  seem  that 
the  vital  force,  to  use  a  rather  questionable  form 
of  language,  withdraws  in  a  certain  measure  the 
organized  being  from  the  realm  of  physical  forces — 
and  this  conclusion  is  one  form  of  contemporary 
neo-vitalism. 


§  4.  PHILOSOPHICAL  NEO-VITALISM. 

Contemporary  neo-vitalism  has  assumed  another 
form,  more  philosophical  than  scientific,  by  which  it  is 
brought  closer  to  vitalism,  properly  so  called.  We 
should  like  to  mention  the  experiment  of  Reinke,1 
in  Germany.  Reinke  is  a  botanist  of  distinction,  who 
distinguishes  the  speculative  from  the  positive  domain 
of  science,  and  cultivates  both  with  success. 

His  ideas  are  analogous  to  those  of  A.  Gautier,  of 
Chevreul,  and  of  Claude  Bernard  himself.  He  thinks, 
with  these  masters,  that  the  mystery  of  life  is  not  to  be 
found  in  the  nature  of  the  forces  that  it  brings  into 
play,  but  in  the  direction  that  it  gives  them.  All  these 
thinkers  are  struck  by  the  order  and  the  direction 
impressed  upon  the  phenomena  which  take  place 
in  the  living  being,  by  their  interconnection,  by  their 
apparent  adaptation  to  an  end,  by  the  kind  of  im- 
pression that  they  give  of  a  plan  which  is  being 
carried  out.  All  these  reflections  lead  Reinke  to 
attach  great  weight  to  the  idea  of  a  "directing 
force." 

The  physico-chemical  energies  are  no  doubt  the 
only  ones  which  are  manifested  in  the  organized 
being,  but  they  are  directed  as  a  blind  man  is  by  his 

1  Reinke,  Die  Welt  als  That;  Berlin,  1899. 


VITALISM.  33 

guide.  It  seems  as  if  a  double  accompanies  them  like 
a  shadow.  This  intelligent  guide  of  blind,  material 
force  is  what  Reinke  calls  a  dominant  Nothing 
could  be  more  like  the  bias  and  the  archeus  of  Van 
HelmonL  Material  energies  would  thus  be  paired 
off  with  their  bias,  their  dominants,  in  the  living 
organisms.  In  them  there  would  therefore  be  two  cate- 
gories of  force  :  "  material  forces,"  or  rather,  material 
energies  obeying  the  laws  of  universal  energetics ; 
and  in  the  second  place,  intelligent  "  spiritual  forces," 
the  dominants.  When  the  sculptor  is  working  his 
marble,  in  every  blow  which  elicits  a  spark  there  is 
something  more  than  the  strong  force  of  the  hammer. 
There  is  thought,  the  volition  of  the  artist,  which  is 
realizing  a  plan.  In  a  machine  there  is  more  than 
machinery.  Behind  the  wheels  is  the  object  which 
the  author  had  in  view  when  he  adjusted  them  for  a 
determined  end.  The  energies  spent  in  action  are 
regulated  by  the  adjustment — that  is  to  say,  by  the 
dominants  due  to  the  intellect  of  the  constructor. 

Thus  it  is  in  the  living  machine.  The  dominants 
in  this  case  are  the  guardians  of  the  plan,  the  agents 
of  the  aim  in  view.  Some  regulate  the  functional 
activity  of  the  living  body,  and  some  regulate  its 
development  and  its  construction.  Such  is  the  second 
form,  the  philosophical  form,  extreme  and  teleological, 
of  contemporary  neo-vitalism. 


CHAPTER    IV. 

THE   MONISTIC   THEORY. 

Physico-chemical  Theory  of  Life.  —  latro-mechanism.  —  Des- 
cartes, Borelli. — latro-chemistry. — Sylvius  le  Boe. — The 
Physico-chemical  Theory  of  Life. — Matter  and  Energy. — 
Heterogeneity  is  merely  the  result  of  the  arrangement  or 
combination  of  homogeneous  bodies. — Reservation  relative 
to  the  world  of  thought. — The  Kinetic  Theory. 

THE  unicist  or  monistic  doctrine  gives  us  a  third  way 
of  conceiving  the  functional  activity  of  the  living 
being,  by  levelling  and  blending  its  three  forms  of 
activity — spiritual,  vital,  and  material.  It  was 
expressed  in  the  seventeenth  and  eighteenth  centuries 
in  "iatro-mechanism  "  and  "  iatro-chemistry,"  concep- 
tions to  which  have  more  recently  succeeded  the 
physico-chemical  doctrine  of  life,  and  finally  "current 
materialism." 

Materialism  is  not  only  a  biological  interpretation  ; 
it  is  a  universal  interpretation  applicable  to  the  whole 
of  nature,  because  it  is  based  on  a  determinate  con- 
ception of  matter.  Here  we  find  ourselves  confronted 
by  the  eternal  enigma  discussed  by  philosophers 
relative  to  this  fundamental  problem  of  force  and 
matter.  We  know  what  answers  were  given  to 
the  problem  by  the  Ionic  philosophers — Thales, 
Democritus,  Heraclitus,  and  Anaxagoras,  who  dis- 
carded the  agency  of  every  spiritual  power  external 
34 


THE    MONISTIC    THEORY.  35 

to  matter.  The  explanation  of  the  world,  the 
explanation  of  life,  were  reduced  to  the  play  of 
physical  or  mechanical  forces.  Epicurus,  a  little  later, 
maintained  that  the  knowledge  of  matter  and  its 
different  forms  accounts  for  all  phenomena,  and  there- 
fore for  those  of  life. 

Descartes,  sharply  separating  the  metaphysical 
world — that  is  to  say,  the  soul  defined  by  its  at- 
tribute, thought — from  the  physical  or  material  world 
characterized  by  extension,  practically  came  to  the 
same  conclusions  as  the  materialists  of  antiquity.  To 
him,  as  to  them,  the  living  body  was  a  mere  machine. 

latro-meclianism.  Descartes.  Borelli. — This,  then,  is 
the  theory  of  the  iatro-mechanicians,  of  which  we  may 
consider  Descartes  the  founder,  instead  of  the  Greek 
philosophers.  These  ideas  held  their  own  for  two 
centuries,  and  were  productive  of  such  fruitful  results 
in  the  hands  of  Borelli,  Pitcairn,  Hales,  Bernoulli,  and 
Boerhaave,  as  to  justify  the  jest  of  Bacon  that  "  the 
philosophy  of  Epicurus  had  done  less  harm  to  science 
than  that  of  Plato."  The  iatro-mechanic  school  ten- 
aciously held  its  own  until  Bichat  came  upon  the  scene. 

latro-cliemistry.  Sylvius  le  Boe. — It  was  from  a 
reaction  against  their  exaggerations  that  Stahl 
created  animism,  and  the  Montpellier  school  created 
vitalism.  We  gather  some  idea  of  the  extravagant 
character  of  their  explanations  by  reading  Boerhaave. 
To  this  celebrated  doctor  the  muscles  were  springs, 
the  heart  \vas  a  pump,  the  kidneys  a  sieve,  and  the 
secretions  of  the  glandular  juices  were  produced  by 
pressure ;  the  heat  of  the  body  was  the  result  of  the 
friction  of  the  globules  of  blood  against  the  walls  of 
the  blood-vessels ;  it  was  greater  in  the  lungs  because 
the  vessels  of  the  lungs  were  supposed  to  be  narrower 


36  LIFE   AND   DEATH. 

than  those  of  other  organs.  The  inadequacy  of  these 
explanations  suggested  the  idea  of  completing  them 
by  the  aid  of  the  chemistry  which  was  then  springing 
into  being.  This  chemistry,  rudimentary  as  it  was, 
longed  for  a  share  in  the  government  of  living  bodies 
and  in  the  explanation  of  their  phenomena.  Dis- 
tillations, fermentations,  and  effervescences  are  now 
seen  to  play  their  role,  a  role  which  was  premature 
and  carried  to  excess.  latro-chemistry  from  the 
general  point  of  view  is  only  an  aspect  of  iatro- 
mechanics;  but  it  is  also  an  auxiliary.  Sylvius  le  Boe 
and  Willis  were  its  most  eminent  representatives. 
This  theory  remained  in  the  background  until 
chemistry  made  its  great  advance — that  is  to  say,  in 
the  days  of  Lavoisier.  After  that,  its  importance  has 
gradually  increased,  particularly  in  the  present  day. 
Nowadays,  the  general  tendency  is  to  regard  the 
organic  functional  activity,  or  even  morphogeny — f.e., 
whatever  there  is  that  is  most  peculiar  to  and  char- 
acteristic of  living  beings — as  a  consequence  of  the 
chemical  composition  of  their  substance.  This  is  a 
point  of  capital  importance,  and  to  it  we  must  recur. 

The  Physico-chemical  Theory  of  Life. — Contemporary 
biological  schools  have  made  many  efforts  to  secure 
themselves  from  any  slips  on  the  philosophical  side. 
They  have  avoided  in  most  cases  the  psychological 
problem ;  they  have  deliberately  refrained  from 
penetrating  into  the  world  of  the  soul.  Hence,  the 
pliysico-chemical  theory  of  life  has  been  built  up  free 
from  spiritualistic  difficulties  and  objections.  But 
this  prudence  did  not  exclude  the  tendency.  And 
there  is  no  doubt,  as  Armand  Gautier  said,  that  £  real 
science  can  affirm  nothing,  but  it  also  can  deny 
nothing  outside  observable  facts ;  'y  and  again,  that 


THE   MONISTIC   THEORY.  37 

"only  a  science  progressing  backwards  can  venture  to 
assert  that  matter  alone  exists,  and  that  its  laws  alone 
govern  the  world."  It  is  none  the  less  true  that  by 
establishing  the  continuity  between  inert  matter  and 
living  matter,  we  thereby  render  probable  the  con- 
tinuity between  the  \vorld  of  life  and  the  world  of 
thought 

flatter  and  Energy. — Besides,  and  without  any 
wish  to  enter  into  this  burning  controversy,  it  is 
only  too  evident  that  there  is  no  agreement  as  to  the 
terms  that  are  used,  and  in  particular  as  to  "  matter  " 
and  "laws  of  matter."  It  is  not  necessary  to  repeat 
that  the  geometrical  mould  in  which  Descartes  cast 
his  philosophy  has  long  since  been  broken.  The 
celebrated  philosopher,  in  defining  matter  by  one 
attribute — extension,  does  not  enable  us  to  grasp  its 
activity,  an  activity  revealed  by  all  natural  facts ;  and 
in  defining  the  soul  by  thought  alone,  prevents  us 
from  seeking  in  it  the  principle  of  this  material  activity. 
This  purely  passive  matter,  consisting  of  extension 
alone,  this  bare  matter  was  to  Leibniz  a  pure  concept. 
A  philosopher  of  our  own  time,  M.  Magy,  has  called  it 
a  sensorial  illusion.  The  bodies  of  nature  exhibit  to 
us  matter  clad  with  energy,  formed  by  the  indissoluble 
union  of  extension  with  an  inseparable  dynamical 
principle.  The  Stoics  declared  that  matter  is  mobile 
and  not  immobile,  active  and  not  inert  Leibniz  also 
had  this  in  his  mind  when  he  associated  it  indissolubly 
with  an  active  principle,  an  "entelechy."  Others  have 
said  that  matter  is  "  an  assemblage  of  forces,"  or  with 
P.  Boscovitch,  "  a  system  of  indivisible  points  without 
extension,  centres  of  force,  in  fact"  Space  would  be 
the  geometrical  locus  of  these  points. 

In  this  conception  the  materialistic  school  finds  the 


38  LIFE    AND    DEATH. 

explanation  of  all  phenomenality.  Physical  properties, 
vital  phenomena,  psychical  facts,  all  have  their  founda- 
tion in  this  immanent  activity.  Material  activity  is 
a  minimum  of  soul  or  thought  which,  by  continuous 
gradation  and  progressive  complexity,  without  solution 
of  continuity,  without  an  abrupt  transition  from  the 
homogeneous  to  the  heterogeneous,  rises  through  the 
series  of  living  beings  to  the  dignity  of  the  human 
soul.  The  observation  ot  the  transitions,  an  imperfect 
tracing  of  the  geometrical  method  of  limits,  thus 
enables  us  to  pass  from  material  to  vital,  and  from 
thence  to  psychical  activity. 

Apparent  Heterogeneity  is  the  Result  of  the  Arrange- 
ment or  the  Combination  of  Homogeneous  Bodies. — In 
this  system,  material  energy,  life,  soul  would  only  be 
more  and  more  complex  combinations  of  the  con- 
substantial  activity  with  material  atoms.  Life  appears 
distinct  from  physical  force,  and  thought  from  life, 
because  the  analysis  has  not  yet  advanced  far  enough. 
Thus,  glass  would  appear  to  the  ancient  Chaldeans 
distinct  from  the  sand  and  salt  of  which  they  made  it. 
In  the  same  way,  again,  water,  to  modern  eyes,  is 
distinct  from  its  constituents,  oxygen  and  hydrogen. 
The  whole  difficulty  is  that  of  explaining  what  this 
"arrangement"  of  the  elements  can  introduce  that 
is  new  in  the  aspect  of  the  compound.  We  must 
know  what  novelty  and  apparent  homogeneity  the 
variety  of  the  combinations,  which  are  only  special 
arrangements  of  the  elementary  parts,  may  produce  in 
the  phenomena.  But  we  do  not  know,  and  it  is  this 
ignorance  which  leads  us  to  consider  them  as  hetero- 
geneous, irreducible,  and  distinct  in  principle.  The 
vital  phenomenon,  the  complexus  of  physico-chemical 
facts,  thus  appears* to  us  essentially  different  from 


THE   MONISTIC  THEORY.  39 

those  facts,  and  that  is  why  we  picture  to  ourselves 
"  dominants "  and  "  directing  forces "  more  or  less 
analogous  to  the  sidereal  guiding  principle  of  Kepler, 
which,  before  the  discover}*  of  universal  attraction, 
regulated  the  harmony  of  the  movements  of  the 
planets. 

A  Reservation  relative  to  tJie  Psycliical  Order. — 
The  scientific  mind  has  shown  in  every  age  a  real 
predilection  towards  the  mechanical  or  materialistic 
theory.  Contemporary  scientists  as  a  whole  have 
accepted  it  in  so  far  as  it  blends  the  vital  and  the 
physical  orders.  Objections  and  contradictions  are 
only  offered  in  the  realm  of  psychology.  A.  Gautier, 
for  example,  has  contested  with  infinite  originality 
and  vigour  the  claims  of  the  materialists  who  would 
reduce  the  phenomenon  of  thought  to  a  material 
phenomenon.  The  most  general  characteristic  of 
material  phenomenality  is — as  we  shall  later  see — 
that  it  may  be  considered  as  a  mutation  of  energy — 
£fc,  it  obeys  the  laws  of  energetics.  Now  thought, 
says  A.  Gautier,  is  not  a  form  of  material  energy. 
Thought,  comparison,  volition,  are  not  acts  of  material 
phenomenality;  they  are  states.  They  are  realities; 
they  have  no  mass ;  they  have  no  physical  existence. 
They  respond  to  adjustments,  arrangements,  and 
concerted  groupings  of  material  manifestations  of 
chemical  molecules.  They  escape  the  laws  of 
energetics. 

Kinetic  Tlteory. — We  shall  lay  aside  for  a  moment 
this  serious  problem  relative  to  the  limits  of  the  world 
of  conscious  thought  and  of  the  world  of  life.  It  is  on 
the  other  side,  on  the  frontiers  of  living  and  inani- 
mate nature,  that  the  mechanical  view  triumphs.  It 
has  furnished  a  universal  conception  agreeing  with 

4 


40  LIFE   AND   DEATH. 

phenomena  of  every  kind — viz.,  the  kinetic  theory, 
which  ascribes  everything  in  nature  to  the  movements 
of  particles,  molecules,  or  atoms. 

The  living  and  the  physical  orders  are  here  reduced 
to  one  unique  order,  because  all  the  phenomena  of  the 
sensible  universe  are  themselves  reduced  to  one  and 
the  same  mechanics,  and  are  represented  by  means  of 
the  atom  and  of  motion.  This  conception  of  the 
world,  which  was  that  of  the  philosophers  of  the  Ionic 
school  in  the  remotest  antiquity,  which  was  modified 
later  by  Descartes  and  Leibniz,  has  passed  into 
modern  science  under  the  name  of  the  kinetic  theory. 
The  mechanics  of  atoms  ponderable  or  imponderable, 
would  contain  the  explanation  of  all  phenomenality. 
If  it  were  a  question  of  physical  properties  or"  vital 
manifestations,  the  objective  world  in  final  analysis 
would  offer  us  nothing  but  motion.  Every  pheno- 
menon would  be  expressed  by  an  atomistic  integral, 
and  that  is  the  inner  reason  of  the  majestic  unity 
which  reigns  in  modern  physics.  The  forces  which 
are  brought  into  play  by  Life  are  no  longer  to 
be  distinguished  in  this  ultimate  analysis  from 
other  natural  forces.  All  arc  blended  in  molecular 
mechanics. 

The  philosophical  value  of  this  theory  is  undeniable. 
It  has  exercised  on  physical  science  an  influence  which 
is  justified  by  the  discoveries  which  it  has  suggested. 
But  to  biology,  on  the  other  hand,  it  has  lent  no  aid. 
It  is  precisely  because  it  descends  too  deeply  into 
things,  and  analyzes  them  to  the  uttermost,  that  it 
ceases  to  throw  any  light  upon  them.  The  distance 
between  the  hypothetical  atom  and  the  apparent  and 
concrete  fact  is  too  great  for  the  one  to  be  able  to 
throw  light  on  the  other  The  vital  phenomenon 


THE   MONISTIC  THEORY.  4! 

vanishes  with  its  individual  aspect;  its  features  can 
no  longer  be  distinguished. 

Besides,  a  whole  school  of  contemporary  physicists 
(Ostwald  of  Leipzig,  Mach  of  Vienna)  is  beginning  to 
cast  some  doubt  on  the  utility  of  the  kinetic  hypothesis 
in  the  future  of  physics  itself,  and  is  inclined  to  pro- 
pose to  substitute  for  it  the  theory  of  energetics.  We 
shall  see,  in  every  case,  that  this  other  conception,  as 
universal  as  the  kinetic  theory,  tlie  theory  of  Energy, 
causes  a  vivid  light  to  penetrate  into  the  depths  of  the 
most  difficult  problems  in  physiology. 

Such  are,  with  their  successive  transformations,  the 
three  principal  theories,  the  three  great  currents 
between  which  biology  has  been  tossed  to  and  fro. 
They  are  sufficiently  indicative  of  the  state  of  positive 
science  in  each  age,  but  one  is  astonished  that  they 
are  not  more  so;  and  this  is  due  to  the  fact  that  these 
conceptions  are  too  general.  They  soar  too  high  above 
reality.  More  characteristic  in  this  respect  will  be 
particular  theories  of  the  principal  manifestations  of 
living  matter,  of  its  perpetuity  by  generation,  of  the 
development  by  which  it  acquires  its  individual  form, 
on  heredity.  It  is  here  that  it  is  of  importance  to 
grasp  the  progressive  march  of  science — that  is  to  say, 
the  design  and  the  plan  of  the  building  which  is  being 
erected,  "  blindly,  so  to  speak,"  by  the  efforts  of  an 
army  of  workers,  an  army  becoming  more  numerous 
day  by  day. 


CHAPTER    V. 

THE      EMANCIPATION      OF      SCIENTIFIC      RESEARCH 
FROM   THE   YOKE    OF    PHILOSOPHICAL   THEORIES. 

The  excessive  use  of  Hypothetical  Agents  in  Physiological 
Explanations — §  I.  Vital  Phenomena  in  Ftdly-constituted 
Organisms  —  Provisory  Exclusion  of  the  Morphogenic 
idea — The  Realm  of  the  Morphogenic  Idea  as  the 
Sanctuary  of  Vital  Force — §  2.  The  Physiological  Domain 
properly  so  called — Harmony  and  Connection  of  Pheno- 
mena—  Directive  Forces  —  Claude  Bernard's  Work  — 
Exclusion  of  Vital  Force,  of  Final  Cause,  of  the  "  Caprice  " 
of  Living  Nature  —  Determinism  —  The  Comparative 
Method  —  Generality  of  Vital  Phenomena  —  Views  of 
Pasteur. 

THE  theories  whose  history  we  have  just  sketched 
in  broad  outline  long  dominated  science  and  exer- 
cised their  influence  on  its  progress. 

This  domination  has  ceased  to  exist.  Physiology- 
has  emancipated  itself  from  their  sway,  and  this, 
perhaps,  is  the  most  important  revolution  in  the  whole 
history  of  biology.  Animism,  vitalism,  materialism, 
have  ceased  to  exercise  their  tyranny  on  scientific 
research.  These  conceptions  have  passed  from  the 
laboratory  to  the  study;  from  being  physiological, 
they  have  become  philosophical. 

This  result  is  the  work  of  the  physiologists  of  sixty 

years  ago.     It  is  also  the  consequence  of  the  general 

march  of  science  and  of  the  progress  of  the  scientific 

spirit,  which  shows  a  more  and  more  marked  tendency 

42 


EMANCIPATION   OF   SCIENTIFIC   RESEARCH.        43 

to  separate  completely  the  domain  of  facts  from  the 
domain  of  hypotheses. 

Excessive  Use  of  HypotJietical  Agents  in  Physio- 
logical Explanations. — It  may  be  said  that  in  the 
early  part  of  the  nineteenth  century,  in  spite  of  the 
efforts  of  a  few  real  experimenters  from  Harvey  to 
Spallanzani,  Hales,  Laplace,  Lavoisier,  and  Magendie, 
the  science  of  the  phenomena  of  life  had  not  followed 
the  progress  of  the  other  natural  sciences.  It  remained 
in  the  fog  of  scholasticism.  Hypotheses  were  mingled 
with  facts,  and  imaginary  agents  carried  out  real  acts, 
in  inexpressible  confusion.  The  soul  (animism),  the 
vital  force  (vitalism),  and  the  final  cause  (finalism, 
teleology)  served  to  explain  everything. 

In  truth,  it  was  also  at  this  time  that  physical 
agents,  electric  and  magnetic  fluids,  or,  again,  chemical 
affinity,  played  an  analogous  part  in  the  science  of 
inanimate  nature.  But  there  was  at  least  this 
difference  in  favour  of  physicists  and  chemists,  that 
when  they  had  attributed  some  new  property  or 
aptitude  to  their  hypothetical  agents  they  respected 
what  they  attributed.  The  physiological  physicians 
respected  no  law,  they  were  subject  to  no  restraint. 
Their  vital  force  was  capricious;  its  spontaneity  made 
anticipation  impossible;  it  acted  arbitrarily  in  the 
healthy  body;  it  acted  more  arbitrarily  still  in  the 
diseased  body.  All  the  subtlety  of  medical  genius 
was  called  into  play  to  divine  the  fantastic  behaviour 
of  the  spirit  of  disease.  If  we  speak  here  of  physio- 
logists and  doctors  alone  and  do  not  quote  biologists, 
it  is  because  the  latter  had  not  yet  made  their 
appearance  as  authorities ;  their  science  had  remained 
purely  descriptive,  and  they  had  not  yet  begun  to 
explain  phenomena. 


44  LIFE   AND   DEATH. 

Such  was  the  state  of  things  during  the  first  years 
of  the  nineteenth  century.  It  lasted,  thanks  to  the 
founders  of  contemporary  physiology — Claude  Bernard 
in  France,  and  Briicke,  Dubois-Reymond,  Helmholtz, 
and  Ludwig  in  Germany — until  a  separation  took 
place  between  biological  research  and  philosophical 
theories.  This  delimitation  operated  in  physiology 
properly  so  called — i.e.  in  a  branch  of  the  biological 
domain  in  which  as  yet  joint  tenancy  had  been  the 
rule.  An  important  revolution  fixed  the  respective 
divisions  of  experimental  science  and  philosophical 
interpretation.  It  was  understood  that  the  one  ends 
where  the  other  begins,  that  the  one  follows  the  other, 
that  one  may  not  cross  the  other's  path.  There  is 
between  them  only  one  doubtful  region  about  which 
there  is  dispute,  and  this  uncertain  frontier  is  con- 
stantly being  shifted  and  science  daily  gains  what 
philosophy  loses. 

§  i.  VITAL  PHENOMENA  IN  CONSTITUTED 
ORGANISMS. 

A  displacement  of  this  kind  had  taken  place  at  the 
time  of  which  we  speak.  It  was  agreed,  that  as  far  as 
concerns  the  phenomena  which  take  place  in  a  con- 
structed and  constituted  living  organism,  it  would  no 
longer  be  permissible  to  allow  to  intervene  in  their 
explanation  forces  or  energies  other  than  those 
which  are  brought  into  play  in  inanimate  nature. 
Just  as  when  explaining  the  working  of  a  clock, 
the  physicist  will  not  invoke  the  volition  or  the  art 
of  the  maker,  or  the  design  that  he  had  in  view,  but 
only  the  connection  of  causes  and  effects  which  he 
has  utilized ;  so,  for  the  living  machine,  whether  the 


EMANCIPATION   OF  SCIENTIFIC   RESEARCH.        45 

most  complex,  such  as  the  human  body,  or  the  most 
elementary,  such  as  the  cell,  we  may  not  invoke  a 
final  cause,  a  vital  force,  external  to  that  organism 
and  acting  on  it  from  without,  but  only  the  con- 
nections and  the  fluctuations  of  effects  which  are  the 
sole  actual  and  efficient  causes.  In  other  words 
Ludwig,  and  Claude  Bernard  in  particular,  expelled 
from  the  domain  of  active  phenomenality  the  three 
chimeras — Vital  Force,  Final  Cause,  and  the  " Caprice '' 
of  Living  Nature. 

But  the  living  being  is  not  only  a  completely  con- 
structed and  completely  constituted  organism.  It  is  not 
a  finished  clock.  It  is  a  clock  which  is  making  itself, 
a  mechanism  which  is  constructing  and  perpetuating 
itself.  Nothing  of  the  kind  is  known  to  us  in  inani- 
mate nature.  Physiology  has  found — in  what  is 
called  morphogeny — its  temporary  limit  It  is  beyond 
this  limit,  it  is  in  the  study  of  phenomena  by  which 
the  organism  is  constructed  and  perpetuated,  it  is  in 
the  region  of  the  functions  of  generation  and  develop- 
ment, that  philosophical  doctrines  expand  and  flourish. 
This  is  the  present  frontier  of  these  two  powers, 
philosophy  and  science.  We  shall  presently  delimit 
them  more  precisely.  W.  Kiihne,  a  well-known 
scientist  whose  death  is  deplored,  not  in  Germany 
alone,  amused  himself  by  studying  the  division  of 
biological  doctrines  among  the  members  of  learned 
societies  and  in  the  world  of  academies.  He 
summed  up  this  kind  of  statistical  inquiry  by 
saying  in  1898  at  the  Cambridge  Congress,  that 
physiologists  were  nearly  all  advocates  of  the  physico- 
chemical  doctrine  of  life,  and  that  the  majority  of 
naturalists  were  advocates  of  vital  force,  and  of  the 
theory  of  final  causes. 


46  LIFE   AND   DEATH. 

Domain  of  the  Morphogenic  Idea  as  the  Last  Sanc- 
ttiary  of  Vital  Force. — We  see  the  reason  for  this. 
Physiology,  in  fact,  has  taken  up  its  position  in 
the  explanation  of  the  functional  activity  of  the 
constituted  organism — i.e.,  on  a  ground  where 
intervene,  as  we  shall  show  further  on,  no  energies 
and  no  matter  other  than  universal  energies  and 
matter.  Naturalists,  on  the  other  hand,  have  more 
especially  considered — and  from  the  descriptive  point 
of  view  alone,  at  least  up  to  the  times  of  Lamarck 
and  Darwin — the  functions,  the  generation,  the 
development  and  the  evolution  of  species.  Now 
these  functions  are  most  refractory  and  inaccessible 
to  physico-chemical  explanations.  So,  when  the 
time  came  to  give  an  account  of  what  they  had  done, 
the  zoologists  had  substituted  for  executive  agents 
nothing  but  vital  force  under  its  different  names. 
To  Aristotle  it  is  the  vital  force  itself  which,  as  soon 
as  it  is  introduced  into  the  body  of  the  child,  moulds 
its  flesh  and  fashions  it  in  the  human  form.  Con- 
temporary naturalists,  the  Americans  C.  O.  Whitman 
and  C.  Philpotts,  for  example,  take  the  same  line  of 
argument.  Others,  such  as  Blumenbach  and  Necdham, 
in  the  eighteenth  century,  invoked  the  same  division 
under  another  name,  that  of  the  nisus  formativns. 
Finally,  others  play  with  words ;  they  talk  of  heredity, 
of  adaptation,  of  atavism,  as  if  these  were  real,  active, 
and  efficient  beings;  while  they  are  only  appella- 
tions, names  applied  to  collections  of  facts. 

This  region  was  therefore  eminently  favourable 
to  the  rapid  increase  of  hypotheses,  and  so  they 
abounded.  There  were  the  theories  of  Buffon,  of 
Lamarck,  of  Darwin,  of  Herbert  Spencer,  of  E. 
Haeckel,  of  His,  of  Weismann,  of  De  Vries,  and 


EMANCIPATION   OF   SCIENTIFIC   RESEARCH.        47 

of  \V.  Roux.  Each  biologist  of  any  mark  had  his  own, 
and  the  list  is  endless.  But  here  already  this  domain 
of  theoretical  speculation  is  checked  on  various  sides 
by  experiment  J.  Loeb,  a  pure  physiologist,  has 
recently  given  his  researches  a  direction  in  which 
zoology  believes  may  be  found  the  explanation  of  the 
mysterious  part  played  by  the  male  element  in 
fecundation.  On  the  other  hand,  the  first  experi- 
ment of  the  artificial  division  of  the  living  cell 
(merotomy)i  with  its  light  upon  the  part  played  by 
the  nucleus  in  the  preservation  and  regeneration  of 
the  living  form,  is  also  the  work  of  a  physiological 
experimenter.  It  dates  back  to  1852,  and  is  due  to 
Augustus  Waller.  This  experiment  was  made  on  the 
sensitive  nervous  cell  of  the  spinal  ganglions  and  on 
the  motor  cell  of  the  anterior  corn u a  of  the  spinal 
cord.  The  effects  were  correctly  interpreted  twelve 
or  fifteen  years  later.  All  that  zoologists  have  done 
is  to  repeat,  perhaps  unconsciously,  this  celebrated 
experiment  and  to  confirm  the  result. 

Thus  we  see  that  the  attack  upon  the  vitalist 
sanctuary  has  commenced.  But  it  would  be  a  grave 
mistake  to  suppose  that  final  cause  and  vital  force  are 
on  the  point  of  being  dislodged  from  their  entrench- 
ments. Philosophical  speculation  has  an  ample  field 
before  it.  Its  frontiers  may  recede.  For  a  long  time 
yet  there  will  be  room  for  a  more  or  less  modernized 
vitalism. 

§  2.  THE  PHYSIOLOGICAL  DOMAIN  PROPERLY  so 

CALLED. 

Vitalism  is  even  found  installed  in  the  region  of 
physiology,  although  for  the  moment  this  science 
limits  its  ambition  to  the  consideration  of  the  com- 


48  LIFE   AND   DEATH. 

pletely  constructed  organized  being,  perfected  in  its 
form.  The  explanation  of  the  working  of  this  con- 
stituted machine  cannot  be  complete  until  we  take 
into  account  the  harmony  and  the  adjustment  of  its 
parts. 

Harmony  and  Connection  of  Parts :  Directive  Forces. 
— These  constituent  parts  are  the  cells.  We  know 
that  the  progress  of  anatomy  has  resulted  in  the 
cellular  doctrine — i.e.,  in  the  two-fold  affirmation 
that  the  most  complicated  organism  is  composed  of 
microscopic  elements,  the  cells,  all  similar,  true 
stones  of  the  living  building,  and  that  it  derives  its 
origin  from  a  single  cell,  egg,  or  spore,  the  sexual  cell, 
or  cell  of  germination.  The  phenomena  of  life,  looked 
at  from  the  point  of  view  of  the  formed  individual, 
are  therefore  harmonized  in  space ;  just  as,  regarded 
from  the  point  of  view  of  the  individual  in  formation 
and  in  the  species,  they  are  connected  in  time.  This 
harmony  and  this  connection  are  in  the  eyes  of  the 
majority  of  men  of  science  the  most  characteristic  pro- 
perties of  the  living  being.  This  is  the  domain  of  vital 
specificity,  of  the  directive  forces  of  Claude  Bernard  and 
A.  Gautier,  and  of  the  dominants  of  Reinke.  It  is  not 
certain,  however,  that  this  order  of  facts  is  more 
specific  than  the  other.  Generation  and  development 
have  been  considered  by  many  physiologists,  and 
quite  recently  by  Le  Dantec,  as  simple  aspects  or 
modalities  of  nutrition  or  assimilation,  the  common 
and  fundamental  property  of  every  living  cell. 

The  Work  of  Claude  Bernard.  Exclusion  of  Vital 
Force,  of  Vital  Cause,  oj  the  "  Caprice"  of  Living  Nature. 
— It  is  not,  however,  a  slight  advance  or  inconsider- 
able advantage  to  have  eliminated  vitalistic  hypotheses 
from  almost  the  whole  domain  of  present-day  physi- 


ENfAKCIPATION   OF   SCIENTIFIC   RESEARCH.        49 

ology,  and  to  have  them,  as  it  were,  thrown  back  into 
its  hinterland.  This  is  the  work  of  the  scientific  men 
of  the  first  half  of  the  nineteenth  century,  and  parti- 
cularly of  Claude  Bernard,  who  has  thereby  won 
the  name  of  the  founder  or  lawgiver  of  physiology. 
They  found  in  the  old  medical  school  an  obstinate 
adversary  glorying  in  its  sterile  traditions.  In  vain 
was  it  proved  that  vital  force  cannot  be  an  efficient 
cause;  that  it  was  a  creation  of  the  brain,  an  insub- 
stantial phantom  introduced  into  the  anatomical 
marionette  and  moving  it  by  strings  at  the  will  of 
any  one — its  adepts  having  only  to  confer  upon  it  a 
new  kind  of  activity  to  account  for  the  new  act  All 
that  had  been  shown  with  the  utmost  clearness  by 
Bonnet  of  Geneva,  and  by  many  others.  It  had  also 
been  said  that  the  teleological  explanation  is  equally 
futile,  since  it  assigns  to  the  present,  which  exists,  an 
inaccessible,  and  evidently  ultimately  inadequate  cause, 
which  does  not  yet  exist  These  objections  were  in 
vain. 

Determinism. — And  so  it  was  not  by  theoretical 
arguments  that  the  celebrated  physiologist  dealt  with 
his  adversaries,  but  by  a  kind  of  lesson  on  things.  In 
fact  he  was  continually  showing  by  examples  that 
vitalism  and  the  theory  of  final  causes  were  idle  errors 
which  led  astray  experimental  investigation ;  that 
they  had  prevented  the  progress  of  research  and  the 
discovery  of  the  truth  in  every  case  and  on  every 
point  in  which  they  had  been  invoked.  He  laid  down 
the  principle  of  biological  determinism,  which  is  nothing 
but  the  negation  of  the  "caprice"  of  living  nature. 
This  postulate,  so  evident  that  there  was  no  need  to 
enunciate  it  in  the  physical  sciences,  had  to  be  shouted 
from  the  housetops  for  the  benefit  of  supporters  of 


50  LIFE    AND    DEATH. 

vital  spontaneity.  It  is  the  statement  that,  under 
determined  circumstances  materially  identical,  the 
same  vital  phenomena  will  be  identically  reproduced. 
Comparative  Method. — Claude  Bernard  completed 
this  critical  work  by  laying  down  the  laws  of  experi- 
ment on  living  beings.  He  commended  as  the  rational 
method  of  research  the  comparative  method.  This 
should  be,  and  is  in  fact,  the  daily  instrument  of  all 
those  who  work  in  physiology.  It  compels  the 
investigator  in  every  research  bearing  on  organized 
beings  to  institute  a  series  of  tests,  such  that  the 
conditions  which  are  unknown  and  impossible  to 
know  may  be  regarded  as  identical  from  one  test  to 
another ;  and  when  we  are  certain  that  a  single 
condition  is  variable,  it  compels  him  to  discover  the 
character  of  the  condition  we  are  dealing  with,  and 
to  learn  to  appreciate,  and  to  measure  its  influence. 
It  is  safe  to  say  that  the  errors  which  are  daily 
committed  in  biological  work  have  their  cause  in 
some  infraction  of  this  golden  rule.  In  physical 
science  the  obligation  to  follow  the  comparative 
method  is  much  less  felt.  In  most  cases  the  witness 
test1  is  useless.  In  physiology  the  witness  test  is 
indispensable. 

1  In  an  article  on  the  experimental  method  recently  published 
in  the  Dictionnaire  de  Physiologic,  M.  Ch.  Richet  writes  as 
follows: — "We  must  therefore  never  cease  to  carry  out  com- 
parative experiments.  I  do  not  hesitate  to  say  that  this 
comparison  is  the  basis  of  the  experimental  method."  It  is  in 
fact  what  was  taught  by  Claude  Bernard  in  maxim  and  by 
example.  It  is  no  exaggeration  to  assert  that  nine-tenths  of  the 
errors  which  take  place  in  research  work  are  imputable  to  some 
breach  of  this  method.  When  an  investigator  makes  a  mistake, 
save  in  the  case  of  material  error,  it  is  almost  certainly  due  to  the 
fact  that  he  has  neglected  to  carry  out  one  of  the  comparative 


EMANCIPATION   OF   SCIENTIFIC   RESEARCH.        51 

Generality  of  Vital  Phenomena. — If  we  add  that 
Claude  Bernard  opposed  the  narrow  opinion,  so  dear 
to  early  medicine,  which  limited  the  consideration  of 
vitality  to  man,  and  the  contrary  notion  of  the  essential 
generality  of  the  phenomena  of  life  from  man  to  the 
animal,  and  from  the  animal  to  the  plant,  we  shall 
have  given  very  briefly  an  idea  of  the  kind  of  revolu- 
tion which  was  accomplished  about  the  year  1864,  the 
date  of  the  appearance  of  the  celebrated  C  Introduction 
a  la  medecine  experitnentale. 

The  ideas  we  have  just  recalled  seem  to  be  as 
evident  as  they  are  simple.  These  principles  appear 
so  well  founded  that  in  a  measure  they  form  an  in- 
tegral part  of  contemporary  mentality.  What  scientist 
would  nowadays  deliberately  venture  to  explain  some 
biological  fact  by  the  intervention  of  the  evidently 
inadequate  vital  force  or  final  cause?  And  who,  to 

tests  required  in  the  problem  before  him.  The  following  is 
an  instance  which  happened  since  the  above  pages  were 
written : — Several  years  ago  a  chemist  announced  the  exist- 
ence in  the  blood  serum  of  a  ferment,  lipase,  capable  of 
saponifying  fats — that  is  to  say,  of  extracting  from  them  the  fatty 
acid.  From  this  he  deduced  many  consequences  relative  to  the 
mechanism  of  fermentations.  But  on  the  other  hand,  it  has 
been  since  shown  (April  1902)  that  this  lipase  of  the  serum 
does  not  exist  How  did  the  error  arise?  The  author  in 
question  bad  mixed  normally  obtained  serum  with  oil,  and  he 
had  noted  the  acidification  of  the  mixture  ;  he  assured  himself 
of  the  fact  by  adding  carbonate  of  soda.  He  saw  the  alkalinity 
of  the  mixture,  serum  +  oil  +  carbonate  of  soda,  diminish,  and  he 
drew  the  conclusion  that  the  acid  came  from  the  saponified  oil. 
He  did  not  make  the  comparative  test,  serum  +  carbonate  of 
soda.  If  he  had  done  so,  he  would  have  ascertained  that  it  also 
succeeded,  and  that  therefore  as  the  acid  did  not  come  from 
the  saponification  of  the  oil,  since  there  was  none,  its  production 
could  not  prove  the  existence  of  a  lipase. 


52  LIFE  AND  DEATH. 

account  for  the  apparent  inconsistency  of  the  result, 
would  bring  forward  the  "  caprice  "  of  living  nature  ? 
And  who  again  would  openly  dispute  the  utility  of 
the  comparative  method  ? 

What  the  physiologists  of  to-day,  according  to 
Claude  Bernard,  would  no  longer  do,  their  pre- 
decessors would  do,  and  not  the  least  important  of 
them.  Longet,  for  example,  at  a  full  meeting  of  the 
Academic,  apropos  of  recurrent  sensibility,  and  Colin 
(of  Alfort),  communicating  his  statistical  results  on 
the  temperature  of  two  hearts,  accepted  more  or 
less  explicitly  the  indetermination  of  vital  facts.  And 
why  confine  our  remarks  to  our  predecessors?  The 
scientists  of  to-day  are  much  the  same.  So  here 
again  we  see  the  reappearance  of  the  phantom  of 
the  final  cause  in  so-called  scientific  explanations. 
One  fact  is  accounted  for  by  the  necessity  of  the 
self-defence  of  the  organism  ;  another  by  the  necessity 
to  a  warm  blooded  animal  of  keeping  its  temperature 
constant.  Le  Dantec  has  recently  reproached  zoo- 
logists for  giving  as  an  explanation  of  fecundation 
the  advantage  that  an  animal  enjoys  in  having  a 
double  line  of  ancestors.  We  might  as  well  say,  as 
L.  Errera  has  pointed  out,  that  the  inundations  of  the 
Nile  occur  in  order  to  bring  fertility  to  Egypt. 

We  must  not  therefore  depreciate  the  marvellous 
work  which  has  emancipated  modern  physiology  from 
the  tutelage  of  early  theories.  The  witnesses  of  this 
revolution  appreciated  its  importance.  One  of  them 
remarked  as  follows,  on  the  appearance  of  f  Introduc- 
tion a  la  mededne  experimental,  which  contained, 
however,  only  a  portion  of  the  theory : — "  Nothing 
more  luminous,  more  complete,  or  more  profound,  has 
ever  been  written  upon  the  true  principles  of  an  art  so 


EMANCIPATION  OF  SCIENTIFIC   RESEARCH.        53 

difficult  as  that  of  experiment  This  book  is  scarcely 
known  because  it  is  on  a  level  to  which  few  people 
nowadays  attain.  The  influence  it  will  have  on  medical 
science,  on  its  progress,  and  on  its  very  language, 
will  be  enormous.  I  cannot  now  prove  my  assertion, 
but  the  reading  of  this  book  will  leave  so  strong  an 
impression  that  I  cannot  help  thinking  that  a  new 
spirit  will  at  once  inspire  these  splendid  researches." 
This  was  said  by  Pasteur  in  1866.  That  is  what  he 
thought  of  the  work  of  his  senior  and  his  rival,  at  the 
moment  when  he  himself  was  about  to  inspire  those 
"  splendid  researches  "  with  the  movement  of  reform, 
the  importance  and  the  consequences  of  which  have 
no  equivalent  in  the  history  of  science.  By  their 
discoveries  and  their  teaching,  by  their  examples  and 
their  principles,  Claude  Bernard  and  Pasteur  have 
succeeded  in  emancipating  a  portion  of  the  domain  of 
vital  facts  from  the  direct  intervention  of  hypothetical 
agents  and  first  causes.  They  were  compelled,  however, 
to  leave  to  philosophical  speculation,  to  directing 
forces,  to  animism,  to  vitalism,  an  immense  provisory 
field,  the  field  which  corresponds  to  the  functions  of 
generation  and  of  development,  to  the  life  of  the 
species  and  to  its  variations.  Here  we  find  them 
again  in  various  disguises 


BOOK    II. 

THE     DOCTRINE     OF     ENERGY     AND     THE      LIVING 
WORLD. 

Summary:  General  Ideas  of  Life. — Elementary  Life. — Chapter 
I.  Energy  in  General. — Chapter  II.  Energy  in  Biology. — 
Chapter  III.  Alimentary  Energetics. 

GENERAL   IDEAS   OF   LIFE.     ELEMENTARY   LIFE. 

Life  is  the  Sinn-total  of  the  Phenomena  Common 
to  all  Living  Beings.  Elementary  Life. — Living 
beings  differ  more  in  form  and  configuration  than 
in  their  manner  of  being.  They  are  distinguished 
more  by  their  anatomy  than  by  their  physiology. 
There  are,  in  fact,  phenomena  common  to  all,  from 
the  highest  to  the  lowest.  This  is  because  there  is 
that  similar  or  identical  foundation,  that  quid  commune 
which  has  enabled  us  to  apply  to  them  the  common 
name  of  "  living  beings."  Claude  Bernard  gave  to 
this  sum-total  of  manifestations  common  to  all  (nutri- 
tion, reproduction)  the  name  of  elementary  life.  To 
him  general  pliysiology  was  the  study  of  elementary 
life;  the  two  expressions  were  equivalent,  and  they 
were  equivalent  to  a  longer  formula  which  the 
illustrious  biologist  has  given  as  a  title  to  one  of 
his  most  celebrated  works — The  Study  of  the 
Phenomena  Common  to  all  Living  Beings,  Animals, 
54 


GENERAL   IDEAS  OF   LIFE.  55 

and  Plants.  From  this  point  of  view  each  being  is 
distinguished  from  another  being  as  a  given  individual 
and  as  a  particular  species ;  but  all  are  in  some  way 
alike  and  thus  resemble  one  another:  common  life, 
elementary  life,  the  essential  phenomena  of  life;  it  is 
life  itself > 

The  manifestations  of  life  may  therefore  be  regarded 
from  the  point  of  view  of  what  is  most  general  among 
them.  As  we  go  down  the  scale  of  anatomical  organ- 
ization, as  we  pass  from  apparatus  (circulatory', 
digestive,  respiratory,  nervous)  to  the  organs  which 
compose  them,  from  the  organs  to  the  tissues,  and 
finally  from  the  tissues  to  the  anatomical  elements  or 
cells  of  which  they  are  formed,  we  approach  that 
common,  physiological  dynamism  which  is  elementary 
life,  but  we  do  not  actually  reach  it.  The  cell,  the 
anatomical  element,  is  still  a  complicated  structure. 
The  elementary  fact  is  further  from  us  and  lower 
down.  It  is  in  the  living  matter,  in  the  molecule  of 
this  matter,  and  there  we  must  seek  it 

Galen  gave  in  days  gone  by  as  the  object  of 
researches  on  life,  the  knowledge  of  the  use  of  the 
different  organs  of  the  animal  machine;  "de  usu 
partium."  Later,  Bichat  assigned  to  them  as  their 
end  the  determination  of  the  properties  of  tissues. 
Modern  anatomists  and  zoologists  try  to  reach  the 
constituent  element  of  these  tissues — the  cell.  Their 
dream  is  to  construct  a  cellular  physiology,  a  physio- 
logical cytology ;  but  we  must  go  further  than  that. 

1  Le  Dantec  has  objected  to  this  conception  of  phenomena 
common  to  different  living  beings.  He  insists  that  all 
phenomena  which  take  place  in  a  given  living  being  are 
proper  to  him,  and  differ,  however  slightly,  from  those  of 
another  individual.  The  objection  is  more  specious  than  real 

5 


56  LIFE   AND   DEATH. 

General  Physiology,  Celhilar  Physiology,  the 
Energetics  of  Living  Beings. — General  physiology, 
as  was  taught  by  Pfliiger  and  his  school,  claims 
to  go  deeper  down  than  the  apparatus,  or  the 
organ,  or  even  the  cell.  As  in  the  case  of 
physics,  general  physiology  endeavours  to  reach, 
and  really  does  in  many  cases  reach,  as  far  as 
the  molecule.  It  is  not  cellular,  it  is  molecular. 
Already,  in  fact,  the  efforts  of  modern  science  have 
succeeded  in  penetrating  into  the  most  general  pheno- 
mena of  the  living  being — those  attributable  to  living 
matter,  or,  to  speak  more  clearly,  those  which  result 
from  the  play  of  the  universal  laws  of  matter  at  work 
in  this  particular  medium  which  is  the  organized 
being. 

Robert  Mayer  and  Helmholtz  have  the  honour  of 
having  set  physiology  in  the  right  road.  They 
founded  the  energetics  of  living  beings — i.e.,  they 
regarded  the  phenomena  of  life  from  the  point  of 
view  of  energy,  which  is  the  factor  of  all  the  pheno- 
mena of  the  universe. 


CHAPTER   I. 

EXERGY  IX  GEXERAL. 

Origin  of  the  Idea  of  Energy. —The  Phenomena  of  Nature  bring 
into  play  only  two  Elements,  Matter  and  Energy. — 5  i. 
Matter.Hl  2.  Energy.— |  3.  Mechankal  Energy.— |  4. 
Thermal  Energy.— f  >  Chemical  Energy.— §  6.  TheTrans- 
formations  of  Energy.— §  7.  The  Principles  of  Energetics.— 
The  Principle  of  the  Conservation  of  Energy.— §  8.  Career  s 
Principle.— The  Degradation  of  Energy. 

Origin  of  the  Idea  of  Energy. — A  new  term,  namely 
energy,  has  been  for  some  years  introduced  into  natural 
science,  and  has  ever  since  assumed  a  more  and  more 
important  place.  It  is  owing  to  the  English  physicists, 
and  especially  to  the  English  electrical  engineers,  that 
this  expression  has  made  its  way  into  technology,  an 
expression  which  is  part  and  parcel  of  both  languages, 
and  which  has  the  same  meaning  in  both.  The  idea 
it  expresses  is,  in  fact,  of  infinite  value  in  industrial 
applications,  and  that  is  why  its  use  has  gradually 
spread  and  become  generalized.  But  it  is  not  merely 
a  practical  idea.  It  is  above  all  a  theoretical  idea  of 
capital  importance  to  pure  theory.  It  has  become 
the  point  of  departure  of  a  science,  energetics,  which, 
although  born  but  yesterday,  already  claims  to 
embrace,  co-ordinate,  and  blend  within  itself  all  the 
other  sciences  of  physical  and  living  nature,  which  die 
imperfection  of  our  knowledge  alone  had  hitherto 
kept  distinct  and  apart 

57 


58  LIFE    AND    DEATH. 

On  the  threshold  of  this  new  science  we  find  in- 
scribed the.  principle  of  the  conservation  of  energy, 
which  has  been  presented  to  us  by  some  as  Nature's 
supreme  law,  and  which  we  may  say  dominates 
natural  philosophy.  Its  discovery  marked  a  new  era 
and  accomplished  a  profound  revolution  in  our  con- 
ception of  the  universe.  It  is  due  to  a  doctor,  Robert 
Mayer,  who  practised  in  a  little  town  in  Wurtemberg-, 
and  who  formulated  the  new  principle  in  1842,  and 
afterwards  developed  its  consequences  in  a  series  of 
publications  between  1845  and  1851.  They  remained 
almost  unknown  until  Helmholtz,  in  his  celebrated 
memoir  on  the  conservation  of  force,  brought  them  to 
light  and  gave  them  the  importance  they  deserved. 
From  that  time  forward  the  name  of  the  doctor  of 
Heilbronn,  until  then  obscure,  has  taken  its  place 
among  the  most  honoured  names  in  the  history  of 
science.1 

1  Mayer's  claim  to  fame  has  been  disputed.  A  Scotch  physicist, 
P.  G.  Tait,  has  investigated  the  history  of  the  law  of  the  con- 
servation of  energy,  which  is  the  history  of  the  idea  of  energy. 
The  conception  has  taken  time  to  penetrate  the  human  mind, 
but  its  experimental  proof  is  of  recent  date.  P.  G.  Tait  finds  an 
almost  complete  expression  of  the  law  of  the  conservation  of 
energy  in  Newton's  third  law  of  motion — namely,  "the  law  of  the 
equality  of  action  and  reaction,"  or  rather,  in  the  second  ex- 
planation which  Newton  gave  of  that  law.  In  fact,  it  was  from 
this  law  that  Helmholtz  deduced  it  in  1847.  He  showed  that 
the  law  of  the  equality  of  action  and  reaction,  considered  as  a 
law  of  nature,  involved  the  impossibility  of  perpetual  motion, 
and  the  impossibility  of  perpetual  motion  is,  in  another  form,  the 
conservation  of  energy. 

At  a  meeting  of  the  Academy  of  Science,  at  Berlin,  28th 
March  1878,  Du  Bois-Reymond  violently  attacked  Tail's  con- 
tention. The  honour  of  having  been  the  first  to  conceive  of  the 
idea  of  energy  and  conservation  was  awarded  to  Leibniz. 
Newton  had  no  right  to  it,  for  he  appealed  to  divine  intervention 


ENERGY  IN   GENERAL.  59 

As  for  energetics,  of  which  thermodynamics  is  only 
a  section,  it  is  agreed  that  even  if  it  cannot  forthwith 
absorb  mechanics,  astronomy,  physics,  chemistry,  and 
physiology,  and  build  up  that  general  science  which 
will  be  in  the  future  the  one  and  only  science  of 
nature,  it  furnishes  a  preparation  for  that  ideal  state, 
and  is  a  first  step  in  the  ascent  to  definite  progress. 

Here  I  propose  to  expound  these  new  ideas,  in  so 
far  as  they  contain  anything  universally  accessible; 
and  in  the  second  place,  I  propose  to  show  their 
application  to  physiology — that  is  to  say,  to  point  out 
their  role  and  their  influence  in  the  phenomena  of 
life. 

Postulate:  the  Phenomena  of  Nature  bring  into 
play  only  two  Elements,  Matter  and  Energy. — If  we 
try  to  account  for  the  phenomena  of  the  universe, 
we  must  admit  with  most  physicists  that  they 
bring  into  play  two  elements,  and  two  elements  only 
namely,  matter  and  energy.  All  manifestations  are 
exhibited  in  one  or  other  of  these  two  forms.  This, 
we  may  say,  is  the  postulate  of  experimental  science. 

Just  as  gold,  lead,  oxygen,  the  metalloids,  and  the 
metals  are  different  kinds  of  matter,  so  it  has  been 
recognized  that  sound,  light,  heat,  and  generally,  the 
imponderable  agents  of  the  days  of  early  physics,  are 

to  set  the  planetary  system  on  its  path  when  disturbed  by  ac- 
cumulated perturbations.  On  the  other  hand,  Colding  claims  to 
have  drawn  his  knowledge  of  the  law  of  conservation  from 
d'Alembert's  principle.  Whatever  may  be  the  theoretical 
foundations  of  this  law,  we  are  here  dealing  with  its  experi- 
mental proof.  According  to  Tail,  the  proof  can  no  more  be 
attributed  to  R.  Mayer  than  to  Seguin.  The  real  modern 
authors  of  the  principle  of  the  conservation  of  energy,  who  gave 
an  experimental  proof  of  it,  are  Colding,  of  Copenhagen,  and 
Joule,  of  Manchester. 


60  LIFE   AND    DEATH. 

different  varieties  of  energy.  The  first  of  these  ideas 
is  older  and  more  familiar  to  us,  but  it  has  not  for  that 
reason  a  more  certain  existence.  Energy  is  objective 
reality  for  the  same  reason  that  matter  is.  The 
latter  certainly  appears  more  tangible  and  more  easily 
grasped  by  the  senses.  But,  upon  reflection,  we  are 
assured  that  the  best  proof  of  their  existence,  in  both 
cases,  is  given  by  the  law  of  their  conservation — that 
is  to  say,  their  persistence  in  subsisting. 

The  objective  existence  of  matter  and  that  of 
energy  will  therefore  be  taken  here  as  a  postulate  of 
physical  science.  Metaphysicians  may  discuss  them. 
We  have  but  little  room  for  such  a  discussion. 


§  i.  MATTER. 

It  is  certainly  difficult  to  give  a  definition  of 
matter  which  will  satisfy  both  physicists  and  meta- 
physicians. 

Mechanical  Explanation  of  the  Universe.  Matter  is 
Mass. — Physicists  have  a  tendency  to  consider  all 
natural  phenomena  from  the  point  of  view  of  mechanics. 
They  believe  that  there  is  a  mechanical  explanation 
of  the  universe.  They  are  always  on  the  look  out  for 
it,  implicitly  or  explicitly.  They  endeavour  to  reduce 
each  category  of  physical  facts  to  the  type  of  the  facts 
of  mechanics.  They  have  made  up  their  minds  to  see 
nowhere  anything  but  the  play  of  motion  and  force. 
Astronomy  is  celestial  mechanics.  Acoustics  is  the 
mechanics  of  the  vibratory  movements  of  the  air  or  of 
sonorous  bodies.  Physical  optics  has  become  the 
mechanics  of  the  undulations  of  the  ether,  after  having 
been  the  mechanics  of  emission  —  a  wonderful 


ENERGY   IN   GENERAL.  6l 

mechanics  which  represents  exactly  all  the  pheno- 
mena of  light,  and  furnishes  us  with  a  perfect  objective 
image  of  it  Heat,  in  its  turn,  has  been  reduced  to  a 
mode  of  motion,  and  thermodynamics  claims  to  em- 
brace all  its  manifestations.  As  early  as  1812,  Sir 
Humphry  Davy  wrote  as  follows: — "The  immediate 
cause  of  heat  is  motion,  and  the  laws  of  transmission 
are  precisely  the  same  as  those  of  the  transmission 
of  motion."  From  that  time  forth,  this  conception 
developed  into  what  is  really  a  science.  The  constitu- 
tion of  gases  has  been  conceived  by  means  of  two 
elements — particles,  and  the  motions  of  these  particles, 
determined  in  the  strictest  detail  And  finally,  in  spite 
of  the  difficulties  of  the  representation  of  electrical  and 
magnetic  phenomena  after  Ampere  and  before  Maxwell 
and  Hertz,  physicists  have  been  able  to  announce  in  the 
second  half  of  the  nineteenth  century  the  unity  of  the 
physical  forces  realized  in  and  by  mechanics.  From 
that  time  forth,  all  phenomena  have  been  conceived 
as  motion  or  modes  of  motion,  only  differing  essen- 
tially one  from  the  other  in  so  far  as  motions  may 
differ — that  is  to  say,  in  the  masses  of  the  moving 
particles,  their  velocities,  and  their  trajectories.  The 
external  world  has  appeared  essentially  homogeneous ; 
it  has  fallen  a  prize  to  mechanics.  Above  all,  there 
is  heterogeneity  in  ourselves.  It  is  in  the  brain, 
which  responds  to  the  nervous  influx  engendered  by 
the  longitudinal  vibration  of  the  air,  by  the  specific 
sensation  of  sound,  which  responds  to  the  transverse 
vibration  of  the  ether  by  a  luminous  sensation,  and  in 
general  to  each  form  of  motion  by  an  irreducible 
specific  sensation. 

Forty  years  have  passed  since  the  mechanical  ex- 
planation of  the   universe   reached    its   definite   and 


62  LIFE   AND   DEATH. 

perfect  form.  It  dominates  physics  under  the  name 
of  the  theory  of  kinetic  energy.  The  minds  of  men  in 
our  own  time  are  so  strongly  impregnated  with  this 
idea  that  most  scientists  of  ordinary  culture  get  no 
glimpse  of  the  world  of  phenomena  but  by  means  of 
this  conception.  And  yet  it  is  only  an  hypothesis. 
But  it  is  so  simple,  so  intuitive,  and  appears  to  be  so 
thoroughly  verified  by  experiment,  that  we  have 
ceased  to  recognize  its  arbitrary  and  unnecessarily 
contingent  character.  Many  physicists  from  this 
standpoint  consider  the  kinetic  theory  as  an  im- 
perishable monument. 

However,  as  in  the  case  of  H.  Poincare,  the  most 
eminent  physicists  and  mathematicians  are  not  the 
dupes  of  this  system;  and  without  failing  to  recognize 
the  immense  services  which  it  has  rendered  to  science, 
they  are  perfectly  well  aware  that  it  is  only  a  system, 
and  that  there  may  be  other  systems.  Certain  among 
them,  such  as  Ostwald,  Mach,  and  Duhem,  believe 
that  the  monument  is  showing  signs  of  decay,  and  at 
present  the  theory  is  opposed  by  another  theory — 
namely,  the  theory  of  energy. 

The  theory  of  energy  is  usually  considered  and  pre- 
sented as  a  consequence  of  the  kinetic  theory;  but  it 
is  perfectly  independent  of  it,  and  it  is,  in  fact,  without 
relying  on  the  kinetic  theory,  without  assuming  the 
unity  of  physical  forces,  which  are  combined  in  mole- 
cular mechanics,  that  we  shall  expound  the  general 
system. 

This  is  not  the  point  at  issue  for  the  moment.  It  is 
not  a  question  of  deciding  the  reality  or  the  merit  of 
this  or  that  mechanical  explanation ;  it  is  a  question 
of  something  more  general,  because  upon  it  depends 
the  idea  of  matter.  It  is  a  question  of  knowing  if 


ENERGY  IN   GENERAL.  63 

there  are  any  explanations  other  than  mechanical 
The  illustrious  English  physicist,  Lord  Kelvin,  does 
not  seem  willing  to  admit  this.  "I  am  never  satisfied," 
he  said,  in  his  Molecular  Mechanics,  "until  I  have 
made  a  mechanical  model  of  the  object  If  I  can 
make  this  model,  I  understand ;  if  I  cannot,  I  do  not 
understand." 

This  tendency  of  so  vigorous  a  mind  to  be  con- 
tent only  with  mechanical  explanations,  has  been 
that  of  the  majority  of  scientific  men  up  to  the 
present  day,  and  from  it  has  arisen  the  scientific  idea 
of  matter. 

What  is  matter,  in  fact,  to  the  student  of  mechanics? 
It  is  mass.  All  mechanics  is  constructed  of  *"?<«•* 
and  forces.  Laplace  said :  "  The  mass  of  a  body  is  the 
sum  of  its  material  points."  To  Poisson,  mass  is  the 
quantity  of  matter  of  which  a  body  is  composed. 
Matter  is  therefore  confused  with  mass.  Now,  mass 
is  the  characteristic  of  the  motion  of  a  body  under  the 
action  of  a  given  force;  it  defines  obedience  or  resist- 
ance to  the  causes  of  motion ;  it  is  the  mechanical 
parameter;  it  is  the  co-efficient  proper  to  every  mobile 
body;  it  is  the  first  invariant  of  which  a  conception 
has  been  established  by  science. 

In  fact,  the  word  matter  appears  to  be  used  in 
other  senses  by  physicists,  but  this  is  only  apparently 
so.  They  have  but  broadened  the  idea  of  the 
mechanicians.  They  have  characterized  matter  by 
the  whole  series  of  phenomenal  manifestations  which 
are  proportional  to  mass,  such  as  weight,  volume, 
chemical  properties — so  that  we  may  say  that  the 
notion  of  matter  does  not  intervene  scientifically  with 
a  different  signification  from  that  of  mass. 

Two  kinds  of  Matter.     Ponderable  and  Imponder- 


64  LIFE   AND   DEATH. 

able. — In  physics  we  distinguish  between  two  kinds 
of  matter — ponderable,  obeying  the  law  of  universal 
attraction  or  weight,  and  imponderable  matter  or 
ether,  which  we  assume  to  exist  and  to  escape  the 
action  of  that  force.  Ether  has  no  weight,  or  ex- 
tremely little  weight.  It  is  material  in  so  far  as  it 
has  mass.  It  is  its  mass  which  confers  existence  on 
it  from  the  mechanical  point  of  view — a  logical  ex- 
istence, inferred  from  the  necessity  of  explaining  the 
propagation  of  heat,  light,  or  electricity. 

It  may  be  observed  that  the  use  of  mass  really 
comes  to  bringing  another  element,  force,  to  intervene, 
and  we  shall  see  that  force  is  connected  with  energy ; 
thus  it  comes  to  defining  matter  indirectly  by  energy. 
The  two  fundamental  elements  are  not  therefore 
irreducible ;  on  the  contrary,  they  should  be  one  and 
the  same  thing. 

Energy  is  the  only  Objective  Reality. — This  fusion 
into  one  will  become  more  evident  still  when  we 
examine  the  different  kinds  of  energy,  each  of  which 
exactly  corresponds  to  one  of  the  aspects  of  active 
matter.  Shall  we  define  matter  by  extension,  by  the 
portion  of  space  it  occupies,  as  certain  philosophers 
do?  The  physicist  will  answer  that  space  is  only 
known  to  us  by  the  expenditure  of  energy  necessary 
to  penetrate  it  (the  activity  of  our  different  senses). 
And  then  what  is  weight?  It  is  energy  of  position 
(universal  attraction).  And  so  with  the  other  attri- 
butes. So  that  if  matter  were  separated  from  the 
energetic  phenomena  by  means  of  which  it  is  revealed 
to  us — weight  or  energy  of  position,  impenetrability 
or  energy  of  volume,  chemical  properties  or  chemical 
energies,  mass  or  capacity  for  kinetic  energy — the  very 
idea  of  matter  would  vanish.  And  that  comes  to 


ENERGY  IN   GENERAL.  65 

saying  that  fundamentally  there  is  only  one  objective 
reality,  energy. 

Philosophical  Point  of  View. — But  from  the  philo- 
sophical point  of  view  are  there  objective  realities? 
That  is  a  wider  question  which  throws  doubt  upon 
matter  itself,  and  which  it  is  not  our  place  to  investi- 
gate here.  A  metaphysician  may  always  discuss  and 
deny  the  existence  of  the  objective  world.  Jt  may  be 
maintained  that  man  knows  nothing  beyond  his 
sensations,  and  that  he  only  objectivates  them  and 
projects  them  outside  himself  by  a  kind  of  hereditary 
illusion.  We  must  avoid  taking  sides  in  all  these 
difficulties.  Physics  for  the  moment  ignores  them — 
ije^  postpones  their  consideration. 

In  a  first  approximation  we  agree  to  consider 
ponderable  matter  only.  Chemistry  acquaints  us 
with  its  different  forms.  They  are  the  different 
simple  bodies,  metalloids,  metals,  and  the  compound 
bodies,  mineral  or  organic.  Hence  we  may  say  that 
chemistry  is  the  history  of  tJu  transformations  of 
matter.  From  the  time  of  Lavoisier  this  science  has 
followed  the  transformations  of  matter,  balance  in 
hand,  and  ascertains  that  they  are  accomplished 
without  change  of  weight. 

Law  of  the  Conservation  of  Matter. — Imagine  a 
system  of  bodies  enclosed  in  a  closed  vessel,  and  the 
vessel  placed  in  the  scale  of  a  balance.  All  the 
chemical  reactions  capable  of  completely  modifying 
the  state  of  this  system  have  no  effect  upon  the  scale 
of  the  balance.  The  total  weight  is  the  same  before, 
during,  and  after.  It  is  precisely  this  equality  of 
weight  which  is  expressed  in  all  the  equations  with 
which  treatises  on  chemistry  are  filled. 

From  a  higher  point  of  view  we  recognize  here,  in 


66  LIFE   AND   DEATH. 

this  law  of  Lavoisier  or  of  the  conservation  of  weight, 
the  verification  of  one  of  the  great  laws  of  nature 
which  we  extend  to  every  kind  of  matter,  ponderable 
or  not.  It  is  the  law  of  the  conservation  of  matter, 
or  again,  of  the  indestructibility  of  matter — "  Nothing 
is  lost,  nothing  is  created,  all  is  transformation."  This 
is  exactly  what  Tait  held,  this  impossibility  of  creating 
or  destroying  matter  which  at  the  same  time  is  a 
proof  of  its  objective  existence.  This  indestructibility 
of  ponderable  matter  is  at  the  same  time  the  funda- 
mental basis  of  chemistry.  Chemical  analysis  could 
not  exist  if  the  chemist  were  not  sure  that  the  contents 
of  his  vessel  at  the  end  of  his  operations  ought  to  be 
quantitatively,  that  is  to  say  by  weight,  the  same  as  at 
the  beginning,  and  during  the  whole  course  of  the 
experiment.1 

§  2.  ENERGY. 

The  Idea  of  Energy  Derived  from  the  Kinetic 
Theory. — The  notion  of  energy  is  not  less  clear  than 
the  notion  of  matter,  it  is  only  more  novel  to  our 
minds.  We  are  led  to  it  by  the  mechanical  conception 
which  now  dominates  the  whole  of  physics,  the  kinetic 
conception,  according  to  which  in  the  sensible  universe 
there  are  no  phenomena  but  those  of  motion.  Heat, 
sound,  light,  with  all  their  manifestations  so  complex 
and  so  varied,  may,  according  to  this  theory,  be 
explained  by  motion.  But  then,  if  outside  the  brain 
and  the  mind  which  has  consciousness  and  which 
perceives,  Nature  really  offers  us  only  motion,  it 
follows  that  all  phenomena  are  essentially  homo- 

1  It  must  be  added  that  the  absolute  rigour  of  this  law  has 
been  called  in  question  in  recent  researches.  It  would  only 
have  an  approximate  value. 


ENERGY   IN   GENERAL.  67 

geneous  among  one  another,  and  that  their  apparent 
heterogeneity  is  only  the  result  of  the  intervention  of 
our  sensorium.  They  differ  only  in  so  far  as  move- 
ments are  capable  of  differing — that  is  to  say,  in 
velocity,  mass,  and  trajectory.  There  is  something 
fundamental  which  is  common  to  them  and  this  quid 
commune  is  energy.  Thus  the  idea  of  energy  may  be 
derived  from  the  kinetic  conception,  and  this  is  the 
usual  method  of  exposition. 

This  method  has  the  great  inconvenience  of  causing 
an  idea  which  lays  claim  to  reality  to  depend  upon  an 
hypothesis.  And  besides  that,  it  gives  a  view  of  it 
which  may  be  false.  It  makes  of  the  different  forms 
of  energy  something  more  than  varieties  which  are 
equivalent  to  one  another.  It  makes  of  them  one  and 
tJie  same  thing.  It  blends  into  one  the  modalities  of 
energy  and  mechanical  energy.  For  the  experimental 
idea  of  equivalence,  the  kinetic  theory  substitutes  the 
arbitrary  idea  of  the  equality,  the  blending,  and  the 
fundamental  homogeneity  of  phenomena.  This  no 
doubt  is  how  the  founders  of  energetics,  Helmholtz, 
Clausius,  and  Lord  Kelvin  understood  things.  But  a 
more  attentive  study  and  a  more  scrupulous  deter- 
mination not  to  go  beyond  the  teaching  of  experiment 
should  compel  us  to  reform  this  manner  of  looking  at 
it  And  it  is  Ostwald's  merit  that,  after  Hamilton,  he 
insisted  on  this  truth — that  the  various  kinds  of 
physical  magnitudes  furnished  by  the  observation  of 
phenomena  are  different  and  characteristic.  In  par- 
ticular, we  may  distinguish  among  them  those  which 
belong  to  the  order  of  scalar  magnitudes  and  others 
which  are  of  the  order  of  vector  magnitudes, 

TJie  Idea  of  Energy  derived  from  the  Connection 
of  Phenomena. — The  idea  of  energy  is  not  absolutely 


68  LIFE   AND   DEATH. 

connected  with  the  kinetic  theory,  and  it  should  not 
be  exposed  therefore  to  the  vicissitudes  experienced 
by  that  theory.  It  is  of  a  higher  order  of  truth.  We 
can  derive  it  from  a  less  unsafe  idea,  namely  that  of 
the  connection  of  natural  phenomena.  /To  conceive  it 
we  must  get  accustomed  to  this  primordial  truth,  that 
there  are  no  plienomena  isolated,  in  time  and  space. 
This  statement  contains  the  whole  point  of  view  of 
energetics.  / 

The  physics  of  early  days  had  only  an  incomplete 
view  of  things,  for  it  considered  phenomena  in- 
dependently the  one  of  the  other. 

Phenomena  for  purposes  of  analysis  were  classed  in 
separate  and  distinct  compartments:  weight,  heat, 
electricity,  magnetism,  light.  Each  phenomenon  was 
studied  without  reference  to  that  it  succeeded  or  that 
which  should  follow.  Nothing  could  be  more  artificial 
than  such  a  method  as  this.  In  fact,  there  is  a 
sequence  in  everything,  everything  is  connected  up, 
everything  precedes  and  succeeds  in  nature — in  nature 
there  are  only  series.  The  isolated  fact  without 
antecedent  or  consequent  is  a  myth.  Each 
phenomenal  manifestation  is  in  solidarity  with 
another.  It  is  a  metamorphosis  of  one  state  of 
things  into  another.  It  is  transformation.  It  implies 
a  state  of  things  anterior  to  that  which  we  are 
observing,  a  phenomenal  form  which  has  preceded 
the  form  of  the  present  moment. 

Now  there  exists  a  link  between  the  anterior  state 
and  the  succeeding  state — that  is  to  say,  between  the 
new  form  which  is  appearing  and  the  preceding  form 
which  is  disappearing  The  science  of  energy  shows 
that  something  has  passed  from  the  first  condition  to 
the  second,  but  covering  itself  as  it  were  with  a  new 


ENERGY   IN   GENERAL.  69 

garment;  in  a  word,  that  something  active  and 
permanent  subsists  in  the  passage  from  one  condition 
to  another,  and  that  what  has  changed  is_qn]y  the 
aspect,  the  appearance. 

This  constanFsomething  which  is  perceived  beneath 
the  inconstancy  and  the  variety  of  forms,  and  which 
circulates  in  a  certain  manner  from  the/,  antecedent 
phenomenon  to  its  successor,  is  energy.  J^/j^  - 

But  still  this  is  only  a  very  vague"  view,  and  it  may 
seem  arbitrary.  It  may  be  made  more  exact  by 
examples  borrowed  from  the  different  categories  of 
natural  phenomena.  There  are  energetic  modalities 
in  relation  with  the  different  phenomenal  modalities. 
The  different  orders  of  phenomena  which  may  be 
presented — mechanical,  chemical,  thermal,  electrical — 
give  rise  to  corresponding  forms  of  energy. 

When  to  a  mechanical  phenomenon  succeeds  a 
mechanical,  thermal,  or  electrical  phenomenon,  we 
say,  embracing  transformation  in  its  totality,  that 
there  has  been  a  transformation  of  mechanical  energy 
into  another  form  of  energy,  mechanical,  thermal,  or 
electrical,  etc. 

This  idea  becomes  more  precise  if  we  examine 
successively  each  of  these  cases  and  the  laws  which 
regulate  them. 


§  3.  MECHANICAL  ENERGY. 

Mechanical  energy  is  the  simplest  and  the  oldest 
known. 

Mechanical  Elements:  Time,  Space,  Force,  Work. 
Power. — Mechanical  phenomena  may  be  considered 
under  two  fundamental  conditions — time  and  space, 


70  LIFE    AND    DEATH. 

which  are,  in  a  measure,  logical  elements,  to  which 
may  be  joined  a  third  element,  itself  experimental, 
having  its  foundations  in  our  sensations — namely, 
force,  work,  or  power. 

The  ideas  of  force,  work,  and  power,  are  drawn  from 
the  experience  man  has  of  his  muscular  activity. 
Nevertheless  the  greatest  mathematical  minds  from 
from  Descartes  to  Leibniz  have  been  obliged  to  define 
and  explain  them  clearly. 

Force. — The  prototype  of  force  is  weight,  universal 
attraction.  Experiment  shows  us  that*  every  body 
falls  as  long  as  no  obstacle  opposes  its  fall.  This  is 
so  universal  a  property  of  matter  that  it  serves  to 
define  it.  The  force,  weight,  is  therefore  the  name 
given  to  the  cause  of  the  fall  of  the  bodies. 

Force  in  general  is  the  cause  of  motion.  Hence 
force  exists  only  in  so  far  as  there  is  motion.  There 
would  be  no  force  without  action.  This  is  Newton's 
point  of  view.  It  did  not  prevail,  and  was  not  the 
point  of  view  of  his  successors.  The  name  of  force 
has  been  given  not  only  to  the  cause  which  produces 
or  modifies  motion,  but  to  the  cause  which  resists  and 
prevents  it.  And  then  not  only  have  forces  in  action 
been  considered  (dynamics),  but  forces  at  rest  (statics). 
Now,  to  Newton  there  was  no  statics.  Forces  do  not 
continue  to  exist  when  they  produce  no  motion ;  they 
are  not  in  equilibrium,  they  are  destroyed. 

The  idea  of  force  therefore  is  a  metaphysical  idea 
which  contains  the  idea  of  cause.  But  it  becomes 
experimental  immediately  it  is  looked  upon  as  resist- 
ing motion,  according  to  the  point  of  view  of  Newton's 
opponents.  Its  foundations  lie  in  the  muscular 
activity  of  man. 

Man    can    support   a   burden    without   bending  or 


ENERGY   IN   GENERAL.  71 

moving.  This  burden  is  a  weight — that  is  to  say,  a 
mass  acted  on  by  the  force  of  weight  Man  resists 
this  force  so  as  to  prevent  its  effect.  If  it  were  not 
annihilated  by  man's  effort^  this  effect  would  be  the 
motion  or  the  fall  of  the  heavy  body.  The  effort  and 
the  force  are  thus  in  equilibrium,  and  the  effort  is 
equal  and  opposite  to  the  force.  It  gives  to  the  man 
who  exercises  it  the  conscious  idea  of  force.  Thus  we 
know  of  force  through  effort.  Every  clear  idea  that 
we  can  have  of  force  springs  from  the  observation  of 
our  muscular  effort. 

The  notion  of  force  is  thus  an  anthropomorphic 
notion.  When  an  effect  is  produced  in  nature  outside 
human  intervention,  we  say  that  it  is  by  something 
analogous  to  what  in  man  is  effort,  and  we  give  to  this 
something  a  name  which  is  also  analogous,  namely 
force.  To  give  a  name  to  effort  and  to  compare 
efforts  in  magnitude,  we  need  not  know  all  about 
them,  nor  need  we  know  in  what  they  essentially 
consist,  of  what  series  of  physical,  chemical,  and 
physiological  actions  they  are  the  consequence.  And 
so  it  is  with  force.  It  is  a  resistance  to  motion  or 
the  cause  of  motion.  This  cause  of  motion  may  be 
an  anterior  motion  (kinetic  force).  It  may  be  an 
anterior  physical  energy  (physical  and  chemical 
forces). 

Forces  are  measured  in  the  C.G.S.  system  by  com- 
paring them  with  the  unit  called  the  Dyne.1  In 
practice  they  are  compared  with  a  much  larger  unit — 
the  gramme,  which  is  the  weight,  the  force  acting  on 
a  unit  of  mass  of  one  centimetre  of  distilled  water  at 
a  temperature  of  4"  C. 

1  The  dyne  is  the  force  which  applied  to  the  unit  of  mass 
produces  a  unit  of  acceleration. 

6 


72  LIFE   AND   DEATH. 

Work. — The  muscular  activity  of  man  may  be 
brought  into  play  in  yet  another  manner.  When  we 
employ  workmen,  as  Carnot  said  in  his  Essai  sur 
fequilibre  et  le  mouvement,  it  is  not  a  question  of 
"knowing  the  burdens  that  they  can  carry  without 
moving  from  their  position,"  but  rather  the  burdens 
that  they  can  carry  from  one  point  to  another.  For 
instance,  a  workman  may  have  to  lift  the  water  from 
the  bottom  of  a  well  to  a  given  height,  and  the  case  is 
the  same  for  the  animals  we  employ.  "  This  is  what 
we  understand  by  force  when  we  say  that  the  force  of 
a  horse  is  equal  to  the  force  of  seven  men.  We  do 
not  mean  that  if  seven  men  were  pulling  in  one 
direction  and  the  horse  in  another  that  there  would  be 
equilibrium,  but  that  in  a  piece  of  work  the  horse 
alone  would  lift,  for  example,  as  much  water  from  the 
bottom  of  a  well  to  a  given  height  as  the  seven  men 
together  would  do  in  the  same  time."  * 

Here,  then,  we  have  to  do  with  the  second  form  of 
muscular  activity, which  is  called  in  mechanics,  "work" 
— at  least,  if  in  the  preceding  quotation  we  attach  no 
particular  importance  to  the  words  "in  the -same 
time,"  and  retain  the  employment  of  muscular  activity 
only  "under  constant  conditions."  Mechanical  work 
is  compared  with  the  elevation  of  a  certain  weight  to  a 
certain  height.  It  is  measured  by  the  product  of  the 
force  (understood  in  the  sense  in  which  it  was  used 
just  now — that  is  to  say,  as  causing  or  resisting  motion) 
and  the  displacement  due  to  this  motion.  The  unit  is 
the  Kilogrammetre — that  is  to  say,  the  work  necessary 
to  lift  a  weight  of  one  kilogramme  to  the  height  of 
one  metre. 

1  These  words  spoil  the  statement,  for  time  has  nothing  to 
do  with  it. 


ENERGY  HI  GENERAL,  75 

It  will  be  remarked  that  the  idea  of  time  does  not 
intervene  in  our  estimation  of  work  The  notion  of 
work  is  independent  of  the  ideas  of  velocity  and 
time.  "  The  greater  or  less  time  that  we  take  to  do 
a  piece  of  work  is  of  no  more  assistance  in  measur- 
ing its  magnitude  than  the  number  of  years  that 
a  man  may  have  taken  to  grow  rich  or  to  ruin  him- 
self can  help  to  estimate  the  present  amount  of  his 
fortune." 

Going  back  to  Carnot's  comparison,  an  employer 
who  employed  his  workmen  only  on  piece-work, — that 
is  to  say,  who  would  only  care  about  the  amount  of 
work  done,  and  would  be  indifferent  to  the  time  that 
they  took  over  it, — would  be  at  the  same  point  of  view 
as  the  advocates  of  the  mechanical  theory.  M. 
Bouasse,  whom  we  follow  here,  has  remarked  that  this 
idea  of  mechanical  work  may  be  traced  back  to 
Descartes.  His  predecessors,  and  Galileo  in  par- 
ticular, had  quite  a  different  idea  of  the  way  in  which 
mechanical  activity  should  be  measured;  and  so, 
among  the  mathematicians  of  the  eighteenth  century, 
Leibniz  and,  later,  John  Bernoulli  were  almost  <alone 
in  looking  at  it  from  this  point  of  view. 

Energy. — Work  thus  understood  is  nuchanical 
energy.  It  represents  the  lasting  and  objective  effect 
of  the  mechanical  activity  independent  of  all  the  cir- 
cumstances under  which  it  was  carried  out.  The 
same  work  may  be  done  under  very  different  con- 
ditions of  time,  velocity,  force,  and  displacement. 
It  is  therefore  the  permanent  element  in  the  variety  of 
mechanical  aspects.  Work,  for  example,  in  the 
collision  of  bodies  when  the  motion  of  a  body  appears 
to  be  destroyed  on  impact  with  another,  reappears  as 
indestructible  vis  viva.  This,  then,  is  exactly  what 


74  LIFE   AND    DEATH. 

we  call  energy;  and  if  we  agree  to  give  it  this  name, 
we  may  say  that  the  conservation  of  energy  is 
invariable  throughout  all  mechanical  transforma- 
tions. 

Distinction  between  Work  and  Force,  and  between 
Energy  and  Work. — The  history  of  mechanics  shows 
us  what  trouble  has  been  taken  and  what  efforts  have 
been  made  to  distinguish  work  (now  mechanical 
energy)  from  force. 

It  is  worth  while  insisting  on  this  distinction.  It 
could  be  easily  shown  that  force  has  no  objective  ex- 
istence. It  has  no  duration,  no  permanence.  It  does 
not  survive  its  effect,  motion.  There  is  no  conserva- 
tion of  force.  It  passes  instantly  from  infinity  to 
zero.  It  is  a  vectorial  magnitude — that  is  to  say,  it 
involves  the  idea  of  direction.  Work,  on  the  other 
hand,  is  the  real  element;  it  is  a  scalar  magnitude 
involving  the  idea  of  opposite  directions,  indicated  by 
the  signs  +  and  - .  Work  and  force  are  hetero- 
geneous magnitudes.  Energy,  and  this  is  the  only 
characteristic  by  which  it  is  distinguished  from  work, 
is  an  absolute  magnitude  to  which  we  may  not  even 
give  opposite  signs. 

An  example  may  perhaps  throw  these  characteristics 
into  relief — namely,  the  hydraulic  press.  We  have  on 
the  platform  exactly  the  work  which  has  been  done 
on  the  other  side.  The  machine  has  only  made  it 
change  its  form.  On  the  contrary,  the  force  has  been 
infinitely  multiplied.  We  may,  in  fact,  consider  an 
infinite  number  of  surfaces  equal  to  that  of  a  small 
piston,  placed  and  orientated  at  will  within  the  liquid ; 
each,  according  to  Pascal's  principle,  will  support  a 
pressure  equal  to  that  which  is  exercised.  As  soon  as 
we  cease  to  support  it,  this  infinity  falls  at  once  to  zero. 


ENERGY   IX   GENERAL.  75 

Now  what  real  thing  could  pass  instantly  from  infinity 
to  zero? 

That  skilful  and  very  able  physiologist,  M.  Chauveau, 
has  endeavoured  to  use  the  same  term  energy  of  con- 
traction for  the  two  phenomena  of  effort  (force)  and 
work.  It  seems,  however,  from  the  point  of  view  of 
the  expenditure  imposed  on  the  organism,  that  these 
two  modes  of  activity,  static  contraction  (effort),  and 
dynamical  contraction  (work),  may  be,  in  fact,  perfectly 
comparable.  But  although  this  manner  of  conceiving 
the  phenomena  may  certainly  be  exact,  and  may  be 
of  great  value,  the  idea  of  force  must  none  the  less 
remain  distinct  from  that  of  work.  The  persistence 
of  the  author  in  violating  established  custom  in  this 
connection  has  prevented  him  from  enabling  mechani- 
cians and  even  some  physiologists  to  understand  and 
accept  very  useful  truths. 

Power. — The  idea  of  mechanical  power  differs  from 
those  of  force  and  work.  The  idea  of  time  must 
intervene.  It  is  not  sufficient,  in  fact,  in  order  to 
characterize  a  mechanical  operation,  to  point  to  the 
task  accomplished.  It  may  be  necessary  or  useful  to 
know  how  much  time  it  required.  This  is  true, 
especially  when  we  are  concerned  with  the  circum- 
stances as  well  as  the  results  of  the  performance  of 
the  work;  and  this  is  the  case  when  we  wish  to 
compare  machines.  We  say  that  the  machine  which 
does  the  work  in  the  shortest  space  of  time  is 
the  most  powerful.  The  unit  of  power  is  the  Kilo- 
gram metre-second — that  is  to  say,  the  power  of  a 
machine  which  does  a  kilogrammetre  in  a  second.  In 
manufactures  we  generally  employ  a  unit  75  times 
greater  than  this — a  horse-power.  This  is  the  power  of 
a  machine  which  does  75  kilogrammetres  a  second, 


76  LIFE   AND   DEATH. 

In  the  electrical  industry  we  measure  by  kilowatts, 
which  are  equivalent  to  1.36  horse  power,  or  by  a  watt, 
a  unit  a  thousand  times  smaller. 

Let  us  add  that  the  power  of  a  machine  is  not  an 
absolute  and  permanent  characteristic  of  the  machine. 
It  depends  on  the  circumstances  under  which  the 
work  is  carried  out,  and  that  is  why,  in  particular,  we 
cannot  appreciate  the  power  of  the  human  machine  in 
comparison  with  industrial  machines.  Experience 
has  shown  that  the  mechanical  power  of  living  beings 
depends  upon  the  nature  of  the  work  they  are  doing. 
In  this  connection  we  may  mention  some  very  inter- 
esting experiments  communicated  to  the  Institute,  in 
the  year  VI.,  by  the  celebrated  physicist,  Coulomb.  A 
man  of  the  average  weight  of  70  kilogrammes  was 
made  to  climb  the  stairs  of  a  house  20  metres  high. 
He  ascended  at  the  rate  of  14  metres  a  minute,  and 
he  performed  this  daily  task  for  four  effective  hours. 
This  work  was  equivalent  to  235,000  kilogrammetres. 
But  if,  instead  of  climbing  without  a  burden,  the  same 
man  had  had  to  carry  a  load,  the  result  would  have 
been  quite  different.  Coulomb's  workman  took  up 
six  loads  of  wood  a  day  to  a  height  of  12  metres 
in  66  journeys,  corresponding  to  a  maximum 
work  of  109,000  instead  of  235,000  kilogrammetres. 
The  mechanical  power  of  the  human  machine 
thus  varied  in  the  two  cases  in  the  ratio  of  235 
to  109. 

The  Two  Aspects  of  Mechanical  Energy :  Kinetic 
and  Potential. — Energy,  or  mechanical  work,  may 
present  itself  in  two  forms — kinetic  energy,  corre- 
sponding to  the  mechanical  phenomenon  which  has 
really  taken  place,  and  potential  energy,  or  the  energy 
of  reserve. 


ENERGY   IX   GENERAL.  77 

A  body  which  has  been  raised  to  a  certain 
height  will,  if  it  be  let  fall,  perform  work  which 
can  be  exactly  measured  in  kilogrammetres  by  the 
product  of  its  weight  into  the  height  it  falls.  Such 
work  may  be  utilized  in  many  ways.  In  this  way, 
for  instance,  public  clocks  are  worked.  Now,  as  long 
as  the  clock-weight  is  raised  and  not  let  go,  and 
as  long  as  it  is  motionless,  the  physics  of  early 
days  would  say  that  there  is  nothing  to  discuss ; 
the  phenomenon  is  the  fall ;  it  is  going  to  take 
place,  but  at  the  present  moment  there  has  been 
no  falL 

In  energetics  we  do  not  reason  in  this  way.  \Ve 
say  that  the  body  possesses  a  capacity  far  work  which 
will  be  manifested  when  the  opportunity  arises,  a 
storage  of  energy,  a  virtual  or  potential  energy,  or 
again,  an  energy  of  position,  which  will  be  transformed 
into  actual  energy  or  real  work  as  soon  as  the  body 
falls. 

Let  us  ask  whence  this  energy  arises.  It  proceeds 
from  the  previous  operation  which  has  raised  the 
weight  from  the  surface  of  the  soil  to  the  position  it 
occupies.  For  example,  if  it  is  a  question  of  the 
weights  of  a  public  clock,  which,  by  its  fall,  will  develop 
in  15  days  the  work  that  is  necessary  to  turn  the 
wheels,  to  strike  the  bell,  and  to  turn  the  hands, 
this  work  ought  to  bring  to  our  minds  the  exactly  equal 
and  opposite  work  done  by  the  clockmaker,  who  has 
to  carry  the  clock-weight  and  to  lift  it  up  from  the 
ground  to  its  point  of  departure.  The  work  of  the 
fall  is  the  faithful  counterpart  of  the  work  of  elevation. 
The  phenomenon  has  therefore  in  reality  two  phases. 
We  find  in  the  second  exactly  what  was  put  into  the 
first,  the  same  quantity  of  energy — />.,  the  same  work. 


78  LIFE   AND   DEATH. 

Between  these  phases  comes  the  intermediary  phase 
of  which  we  say  that  it  is  a  period  of  virtual  or  poten- 
tial energy.  This  is  a  way  of  remembering  in  some 
measure  the  preceding  phenomenon — i.e.,  the  work  of 
lifting  up,  and  of  indicating  the  phenomena  which  will 
follow — i.e.,  the  work  of  the  fall.  And  thus  we  connect 
by  our  thoughts  the  present  situation  with  the  ante- 
cedent and  with  the  consequent  position,  and  it  is 
from  this  consideration  of  continuity  alone  that  the 
conception  of  energy  springs — that  is  to  say,  of  some- 
thing which  is  conserved  and  is  found  to  be  permanent 
in  the  succession  of  phenomena.  This  energy  of 
which  we  lose  no  trace  does  not  appear  to  us  new 
when  it  is  manifested.  Our  imagination  eventually 
materializes  the  idea  of  it.  We  follow  it  as  a  real 
thing,  having  an  objective  existence,  which  is  asleep 
during  the  latent  potential  period,  and  is  revealed  or 
manifested  later. 

Among  other  examples,  that  of  the  coiled  spring 
which  is  unwound  is  particularly  suitable  for  show- 
ing this  fundamental  character  of  the  idea  of 
mechanical  energy,  an  idea  which  is  the  clearest 
of  all.  Machines  are  only  transformers  and  not 
creators  of  mechanical  energy.  They  only  change 
one  form  into  another. 

*""  In  the  same  way,  too,  a  stream  of  water  or  the 
torrent  of  a  mountainous  region  may  be  utilized  for 
setting  in  motion  the  wheels  and  the  turbines  of  the 
factories  situated  in  the  valley.  Its  descent  produces 
the  mechanical  work  which  would  be  a  creation  ex 
nihilo  if  we  do  not  connect  the  phenomenon  with  its 
antecedents.  We  look  on  it  as  a  simple  restitution,  if 
we  think  of  the  origin  of  this  water  which  has  been 
transported  and  lifted  in  some  way  to  its  level  by  the 


ENERGY   IX   GENERAL.  79 

play  of  natural  forces — evaporation  under  the  action 
of  the  sun,  the  formation  of  clouds,  transport  by  winds, 
etc.  And  we  here  again  see  that  a  complex  energy 
has  been  transformed,  in  its  first  phenomenal  con- 
dition, into  potential  energy,  and  that  this  potential 
energy  is  always  expended  in  the  second  phase  with- 
out  loss  or  gain. 

The  Different  Kinds  of  MecJianical  Energy ;  of 
Motion,  of  Position. — There  are  as  many  forms  of 
energy  as  there  are  distinct  categories  of  phenomena 
or  of  varieties  in  these  categories.  Physicists  dis- 
tinguish between  two  kinds  of  mechanical  energy — 
energy  of  motion  and  energy  of  position.  The  energy 
of  position  presents  several  variants — energy  of  dis- 
tance, which  corresponds  to  force :  of  this  we  have  just 
spoken ;  energy  of  surface,  which  corresponds  to  par- 
ticular phenomena  of  surface  tension ;  and  energy  of 
volume  which  corresponds  to  the  phenomena  of  pressure 
Energy  of  motion,  kinetic  energy,  is  measured  in  two 
ways:  as  work  (the  product  of  force  and  displacement, 
W  =fs)  or  as  vis  viva  (half  the  product  of  the  mass 

into  the  square  of  the  velocity  U  =  — ^-.* 

1  We  therefore  notice  that  the  measures  of  force  and  work 
bring  in  mass,  space,  and  time.  The  typical  force,  weight,  is 
given  by  •^.•=mg.  On  the  other  hand,  we  have  by  the  laws  of 

falling  bodies  v=gt ;   s=\gf*',  whence g=  ^-,  •  v/=m  ^-^-;OT,\{ 

F  be  the  force,  M  the  mass,  L  the  space  described,  and  T  the 
time,  we  have  F  =  MLT-S,  which  expresses  what  are  called  the 
dimensions  of  the  force — that  is  to  say,  the  magnitudes  with  their 
degree,  which  enter  into  its  expression.  We  may  thus  easily 
obtain  the  dimensions  of  work  : — 


80  LIFE    AND    DEATH. 


§  4.  THERMAL  ENERGY. 

In  the  elements  of  physics  it  is  nowadays  taught 
that  mechanical  work  may  be  transformed  into  heat, 
and  reciprocally  that  heat  may  be  transformed  into 
mechanical  work.  Friction,  impact,  pressure,  and 
expansion  destroy  or  annihilate  the  mechanical  energy 
communicated  to  a  body  or  to'  the  organs  of  a 
machine.  With  the  disappearance  of  motion  we 
note  the  appearance  of  heat.  Examples  abound. 
The  tyre  of  a  wheel  is  heated  by  the  friction  of  the 
road.  Portions  of  steel  are  warmed  by  the  impact 
with  stone,  as  in  the  old  flint  and  steel.  Two  pieces 
of  ice  were  melted  by  Davy,  who  rubbed  them  one 
against  the  other,  the  external  temperature  being 
below  zero.  The  boiling  of  a  mass  of  water  caused 
by  a  drill  was  noticed  by  Rumford  in  1790,  during 
the  manufacture  of  bronze  cannon.  Metal,  beaten  on 
an  anvil,  is  heated.  A  leaden  ball  flattened  against  a 
resisting  obstacle  shows  increase  of  temperature  carried 
to  the  point  of  fusion.  Finally,  and  symbolically,  we 
have  the  origin  of  fire  in  the  fable  of  Prometheus,  by 
rubbing  together  the  pieces  of  wood  which  the  Hindoos 
called  pramantJia.  Correlation  is  constant  between 
the  thermal  and  mechanical  phenomena,  a  correlation 
that  becomes  evident  as  soon  as  observers  have  ceased 
to  restrict  themselves  to  the  determination  in  isolation 
of  the  one  fact  or  the  other.  There  is  never  any  real 
destruction  of  heat  and  motion  in  the  true  sense  of  the 
word ;  what  disappears  in  one  form  appears  again  in 
another;  just  as  if  something  indestructible  were  ap- 
pearing in  a  series  of  successive  disguises.  This 
impression  is  translated  into  words  when  we  speak 


ENERGY   IN   GENERAL.  8l 

of  the   metamorphosis   of  mechanical   into   thermal 
energy. 

The  Mechanical  Equivalent  of  Heat. — The  inter- 
pretation assumes  a  remarkable  character  of  precision 
which  at  once  strikes  the  mind  when  physics  applies 
to  these  transformations  the  almost  absolute  accuracy 
of  its  measurements.  We  then  find  that  the  rate  of 
exchange  is  invariable.  Transformations  of  heat  into 
motion,  and  of  motion  into  heat,  take  place  according 
to  a  rigorous  numerical  la\v,  which  brings  into  exact 
correspondence  the  quantity  of  each.  Mechanical 
effect  is  estimated,  as  we  have  seen,  by  work,  that  is  in 
kilogrammetres.  Heat  is  measured  in  calories,  the 
calorie  being  the  quantity  of  heat  necessary  to  raise 
from  o°C  to  I  C  a  kilogramme  of  water  (Calorie)  or 
one  gramme  of  water  (calorie).  It  is  found  that 
whatever  may  be  the  bodies  and  the  phenomena 
which  serve  as  intermediaries  for  carrying  out  this 
transformation,  we  must  always  expend  425  kilo- 
grammetres to  create  a  Calorie,  or  expend  0-00234 
Calories  to  create  a  kilogrammetre.  The  number  425 
is  the  mechanical  equivalent  of  the  Calorie,  or,  as  is 
incorrectly  stated,  of  the  heat  It  is  this  constant  fact 
which  constitutes  the  principle  of  tJie  equivalence  of /teat 
and  of  mechanical  work. 


§  5.  CHEMICAL  ENERGY. 

We  cannot  yet  actually  measure  chemical  activity 
directly,  but  we  know  that  chemical  action  may  give 
rise  to  all  other  phenomenal  modalities.  It  is  their 
most  ordinary  source,  and  it  is  to  it  that  industries 
appeal  to  obtain  heat,  electricity,  and  mechanical 


82  LIFE   AND   DEATH. 

action.  In  the  steam  engine,  for  instance,  the  work 
that  is  received  arises  from  the  combustion  of  carbon 
by  the  oxygen  of  the  air.  This  gives  rise  to  the  heat 
which  vaporizes  the  water,  produces  the  tension  of  the 
steam,  and  ultimately  produces  the  displacement  of 
the  piston.  The  theory  of  the  steam  engine  might  be 
reduced  to  these  two  propositions:  chemical  activity 
gives  rise  to  heat,  and  heat  gives  rise  to  motion ;  or  to 
use  the  language  to  which  the  reader  by  now  will  be 
accustomed,  chemical  energy  is  transformed  into 
thermal  energy,  and  that  into  mechanical  energy.  It 
is  a  series  of  phases  and  of  instantaneous  changes,  and 
the  exchange  is  always  affected  according  to  a  fixed 
rate. 

TJie  Measurement  of  Chemical  Energy. — Our  know- 
ledge of  chemical  energy  is  less  advanced  than  that  of 
the  energies  of  heat  and  sensible  motion.  We  have 
not  yet  reached  the  stage  of  numerical  verifications. 
We  can  only  therefore  affirm  the  equivalence  of 
chemical  and  thermal  energies  without  the  aid  of 
numerical  constants,  because  we  do  not  yet,  in  the 
present  state  of  science,  know  how  to  measure 
chemical  energy  directly.  Other  known  energies  are 
always  the  product  of  two  factors:  the  mechanical 
energy  of  position,  or  work,  is  measured  by  the 
product  of  the  force  f,  and  the  displacements;  work 
=/?;  the  mechanical  energy  of  motion,  U  =  ^mv2,  is 
measured  by  the  product  of  the  mass  into  half  the 
square  of  the  velocity.  Thermal  energy  is  measured 
by  the  product  of  the  temperature  and  the  specific 
heat;  electric  energy  by  the  product  of  the  quantity 
of  electricity  (in  coulombs)  and  of  the  electromotive 
force  (in  volts).  As  for  chemical  energy,  we  guess 
that  it  may  be  valued  directly  according  to  Berthollet's 


ENERGY  IN   GENERAL.  83 

system,  adopted  by  the  Norwegian  chemists,  Guldberg 
and  Waage,  by  means  of  the  product  of  the  masses 
and  of  a  force,  or  co-efficient  of  affinity,  which  depends 
on  the  nature  of  the  substances  which  are  brought  to- 
gether, on  the  temperature,  and  on  the  other  physical 
circumstances  of  the  reaction.  On  the  other  hand. 
the  researches  of  M.  Berthelot  enable  us  in  many 
cases  to  obtain  an  indirect  valuation  in  terms  of  the 
equivalent  heat. 

Its  TIL'O  Forms. — It  is  interesting  to  note  that 
chemical  energy  may  also  be  regarded  from  the  two 
states  of  potential  and  kinetic  energy.  The  coal- 
oxygen  system,  to  burn  in  the  furnace  of  the  steam 
engine,  must  be  primed  by  preliminary  work  (local 
ignition),  just  as  the  weight  that  is  raised  and  left 
motionless  at  a  certain  height  requires  a  small 
effort  to  be  detached  from  its  support.  When  this 
condition  is  fulfilled,  energy  is  at  once  manifest. 
We  must  admit  that  it  existed  in  the  latent  state,  in 
the  state  of  chemical  potential  energy.  Under  the 
impulse  received,  the  carbon  combines  with  the 
oxygen  and  forms  carbonic  acid,  C  +  :zO  becomes 
CO2;  potential  energy  is  changed  into  actual  chemical 
energy,  and  immediately  afterwards  into  thermal 
energy.  \Ve  should  have  only  a  very  incomplete  and 
fragmentary  view  of  the  reality  of  things  if  we  were 
to  consider  this  phenomenon  of  combustion  in  isolation. 
We  must  consider  it  in  connection  with  what  has 
actually  created  the  energy  which  it  is  about  to 
dissipate.  This  antecedent  fact  is  the  action  of  the 
sun  upon  the  green  leaf.  The  carbon  which  burns  in 
the  furnace  of  the  machine  comes  from  the  mine  in 
which  it  was  stored  in  the  form  of  coal — that  is  to  say, 
of  a  product  which  was  vegetable  in  its  primitive  form, 


84  LIFE   AND    DEATH. 

and  which  was  formed  at  the  expense  of  the  carbonic 
acid  of  the  air.  The  plant  had  separated,  at  the 
expense  of  the  solar  energy,  the  carbon  from  the 
oxygen  to  which  it  was  united  in  the  carbonic  acid  of 
the  atmosphere.  It  had  created  the  system  C  +  2O. 
So  that  the  solar  energy  produces  the  chemical  poten- 
tial energy  which  was  so  long  before  it  was  utilized. 
Combustion  expends  this  energy  in  making  carbonic 
acid  over  again. 

Materialization  of  Energy. — The  fertility  of  the 
idea  of  energy  is  therefore,  as  we  see  from  all 
these  examples,  due  to  the  relations  it  establishes 
between  the  natural  phenomena  of  which  it  exhibits 
the  necessary  relation,  destroyed  by  the  excessive 
analysis  of  early  science.  /It  shows  us  that  in  the 
world  of  phenomena  there  is  nothing  but  trans- 
formations of  energy.  /And  we  regard  these  trans- 
formations themselves  as  the  circulation  of  a  kind  of 
indestructible  agent  which  passes  from  one  form  of 
determination  to  another,  as  if  it  were  simply  putting 
on  a  fresh  disguise.  If  our  intellect  requires  images 
or  symbols  to  embrace  the  facts  and  to  grasp  their 
relation,  it  may  introduce  them  here.  It  will  materialize 
energy,  it  will  make  of  it  a  kind  of  imaginary  being, 
and  confer  upon  it  an  objective  reality.  And  for  the 
mind,  as  long  as  it  does  not  become  the  dupe  of  the 
phantom  which  it  itself  has  created,  this  is  an 
eminently  comprehensive  artifice  which  enables  us 
to  grasp  readily  the  relations  between  phenomena 
and  their  bond  of  affiliation. 

The  world  appears  to  us  then,  as  we  said  at  the 
outset,  constructed  with  singular  symmetry.  It  offers 
to  us  nothing  but  transformations  of  matter  and 
transformations  of  energy ;  these  two  kinds  of  meta- 


ENERGY  IX  GENERAL.  85 

moiphoses  being  governed  by  two  laws  equally 
inevitable,  the  conservation  of  matter  and  the  con- 
servation of  energy.  The  first  of  these  laws  expresses 
the. fact  that  matter  is  indestructible,  and  passes 
from  one  phenomenal  determination  to  another  at 
a  rate  of  equivalence  measured  by  weight;  the 
second,  that  energy  is  indestructible,  and  that  it 
passes  from  one  phenomenal  determination  to  another 
at  a  rate  of  equivalence  fixed  for  each  category  by 
the  discoveries  of  the  physicists. 


$  6.  TRANSFORMATIONS  OF  ENERGY. 

The  idea  of  energy  has  become  the  point  of  departure 
of  a  science,  Energetics t  to  the  establishment  of  which 
a  large  number  of  contemporary  physicists,  among 
whom  are  Ostwald,  Le  Chatdier,  etc,  have  devoted 
their  efforts.  It  is  the  study  of  phenomena,  regarded 
from  the  point  of  view  of  energy.  1  have  said  that  it 
claims  to  co-ordinate  and  to  embrace  all  other  sciences. 

The  first  object  of  energetics  should  be  the  con- 
sideration of  the  different  forms  of  energy  at  present: 
known,  their  definition  and  their  measurement.  This 
is  what  we  have  just  done  in  broad  outline. 

In  the  second  place,  each  form  of  energy  must  be 
regarded  with  reference  to  the  rest,  so  as  to  determine 
if  the  transformation  of  this  into  that  is  directly 
realizable,  and  by  what  means,  and,  finally,  according 
to  what  rate  of  equivalence.  This  new  chapter  is  a 
laborious  task  which  would  compel  us  to  traverse  the 
whole  field  of  physics. 

Of  this  long  examination  we  need  only  concern 
ourselves  here  with  three  or  four  results  which  will  be 


86  LIFE   AND   DEATH. 

more  particularly  important  in  the  case  of  applications 
to  living  beings.  They  refer  to  mechanical  energy,  to 
the  relations  of  thermal  energy  and  chemical  energy, 
to  the  complete  role  of  thermal  energy,  and  finally  to 
the  extreme  adaptability  of  electrical  energy. 

1 .  Transformation     of     Mechanical    Energy.  — 
Mechanical  energy  may  change  into  every  other  form 
of  energy,  and  all  others  can  change  into  it,  with  but 
one  exception,  that  of  chemical  energy.      Mechanical 
effort  does  not  produce  chemical  combination.     What 
we  know  of  the  part  played  by  pressure  in  the   re- 
actions of  dissociation   seems    at    first    to   contradict 
this  assertion.     But  this  is  only  in  appearance.     Pres- 
sure intervenes  in  these  operations  only  as  preliminary 
zvork  or  priming,  the  purpose  of  which  is  to  bring  the 
bodies  into  contact  in  the  exact  state  in  which  they 
must  be  for  the  chemical  affinities  to  be  able  to  enter 
into  play. 

2.  Transformation  of  Thermal  Energy ;  Priming. 
— Thermal   (or   luminous)   energy   does    not  change 
directly  into  chemical  energy.     In  fact,  heat  and  light 
favour  and  even  determine  a  large  number  of  chemical 
reactions;    but  if  we  go  down  to- the  foundation  ot 
things   we  are   not  long  before  we  feel  assured  that 
heat    and    light    only    serve    in    some    measure    for 
priming    for    the    phenomenon,     for    preparing    the 
chemical    action,    for    bringing    the   body   into    the 
physical    state    (liquid,    steam)    or    to    the  degree   of 
temperature  (400°  C.  for  instance,  for  the  combination 
of  oxygen  and  hydrogen)  which  are  the  preliminary 
indispensable  conditions  for  the  entry  upon  the  scene 
of  chemical  affinities. 

On   the   contrary,   chemical   energy  may  really  be 
transformed    into    thermal    energy.     We     have     an 


ENERGY   IN   GENERAL.  87 

instance  of  this  in  the  reactions  which  take  place 
without  the  aid  of  external  energy;  and  again,  in 
those  very  numerous  cases  which,  such  as  the  com- 
bustion of  hydrogen  and  carbon,  or  the  decomposition 
of  explosives,  the  reactions  continue  when  once  primed. 
I  may  make  a  further  observation  apropos  of  thermal 
and  photic  energy.  These  are  not  two  really  and 
essentially  distinct  forms,  as  was  thought  in  the  early 
days  of  physics.  When  we  consider  things  objectively, 
there  is  absolutely  no  light  without  heat;  light  and 
heat  are  one  and  the  same  agent  According  as  it  is 
at  this  or  that  degree  of  its  scale  of  magnitude,  it 
makes  a  stronger  impression  on  the  skin  ^sensation  of 
heat)  or  on  the  retina  (sensation  of  light}  of  man  and 
animals.  The  difference  may  be  put  down  to  the 
diversity  of  the  work  and  not  to  that  of  the  agent. 
The  kinetic  theory  shows  us  that  the  agent  is 
qualitatively  identical.  The  words  heat  and  light 
only  express  the  chance  of  the  meeting  of  the  radiant 
agent  with  a  skin  and  a  retina.  At  the  lowest  degree 
of  activity  this  agent  exerts  no  action  on  the  termina- 
tions of  the  thermal  cutaneous  nerves,  nor  on  the 
optic  nerve-terminations.  As  this  degree  is  raised 
the  former  of  these  nerves  are  affected  'cold,  heat;  and 
are  so  to  the  exclusion  of  the  nerves  of  vision.  Then 
they  are  both  affected  (sensation  of  heat  and  light), 
and  finally,  beyond  that,  sight  alone  is  affected.  The 
transformation  of  one  energy  into  the  other  is  there- 
fore here  reduced  to  the  possibility  of  increasing  or 
decreasing  the  intensity  of  the  action  of  this  common 
agent  in  the  exact  proportions  suitable  for  passing 
from  one  of  the  conditions  to  the  other;  and  this  is 
easy  when  it  is  a  question  of  going  up  the  scale  in  the 
case  of  light,  and,  on  the  contrary,  it  is  not  realizable 

7 


LIFE    AND    DEATH. 

directly,  that  is  to  say  without  external  assistance, 
when  it  is  a  question  of  going  down  the  scale  again,  in 
the  case  of  heat. 

3.  Heat  a  Degraded  Form   of  Energy. — We   have 
seen  that  thermal  energy  is  not  directly  transformed 
into  chemical  energy.    There  is  yet  another  restriction 
in  the  case  of  this  thermal  energy  if  we  study  the  laws 
which  govern  the  circulation  and  the  transformations 
of  thermal  energy;  and  the  most  important  comes  from 
the  impossibility  of  transporting  it  from  a  body  at 
a  lower  temperature  to  a  body  at  a  higher  temperature. 
On    the    whole,   and    because  of    these    restrictions, 
thermal  energy  is  an   imperfect  variety  of  universal 
energy,  or,  as  the  English  physicists  call  it,  a  degraded 
form. 

4.  Simple  Transformations  of  Electrical  Energy.     Its 
Intermediary  Ro.'e. — On  the  other  hand, electrical  energy 
represents  a  perfected  and  infinitely  advantageous  form 
of  this  same  universal  energy,  and  this  explains  the  vast 
development  of  its  industrial  applications  within  less 
than  a  century.     It  is  not  that  it  is  better  known  than 
the  others  in  its  nature  and  in  the  secret  of  its  action. 
On  the  contrary,  there  is  more  dispute  than  ever  as  to 
its  nature.    To  some,  electricity,  which  is  transported 
and  propagated  with  the  speed  of  light,  is  a  real  flux 
of  the  ether  as  was  taught  by  Father  Secchi,  who 
compared  it  to  a  current  of  water  in  a  pipe.     It  would 
do  its  work,  just  as  the  water  of  the  mill  does  its 
work  by  flowing  over  a  wheel  or  through  a  turbine. 
Electricity,  like    water   in   this   case,   would    not   be 
an    energy   in    itself,   but   a    means    of    transporting 
energy. 

To  others,  such  as  Clausius,  Hertz,  and  Maxwell,  it 
is  not  so;  the  electric  current  is  not  a  transport  of 


ENERGY  IN  GENERAL-  89 

energy.  It  is  a  state  of  the  ether  of  a  peculiar, 
specific  kind,  periodically  produced  (electric  oscilla- 
tion), and  propagated  with  a  speed  of  the  order  of 
that  of  light. 

However  that  may  be,  what  constitutes  the  essential 
peculiarity  of  electrical  energy,  and  what  causes  its 
value,  is  that  it  is  an  incomparable  agent  of  trans- 
formation. Every  known  form  of  energy  may  be 
converted  into  it,  and  inversely,  electrical  energy  may 
be  changed  with  the  utmost  facility  into  all  other 
energies.  This  extreme  adaptability  assigns  to  it 
the  part  of  an  intermediary  between  the  other  less 
tractable  agents.  Mechanical  energy,  for  instance, 
lends  itself  with  difficulty  to  the  production  of  light, 
that  is  to  say,  to  a  metamorphosis  into  photic  energy 
(a  variety  of  thermal  energy).  A  fall  of  water  cannot 
be  directly  utilized  for  lighting  purposes.  The 
mechanical  work  of  this  fall,  which  cannot  be 
exploited  in  its  present  form,  serves  to  set  in 
motion  in  industrial  lighting  the  installations,  the 
electric  machines,  and  the  dynamos  which  feed  the 
incandescent  lamps.  Mechanical  work  is  changed 
into  electrical  energy,  and  it,  in  its  turn,  into  thermal 
or  photic  energy.  Electricity  has  here  played  the  part 
of  a  useful  intermediary. 

The  last  part  of  energetics  must  be  consecrated  to 
the  study  of  the  general  principles  of  this  science. 
These  principles  are  two  hi  number,  the  principle  of 
the  conservation  of  energy,  or  Mayer's  principle,  and 
the  principle  of  the  transformation  of  energy,  or 
Carnot's  principle.  The  doctrine  of  energy  thus 
reduces  to  two  fundamental  laws  the  multitude  of 
laws,  often  known  as  "general,"  to  which  natural 
science  is  subject. 


go  LIFE    AND    DEATH. 

§  7.  THE  PRINCIPLE  OF  THE  CONSERVATION 
OF  ENERGY. 

In  all  that  precedes,  the  principle  of  conservation  has 
intervened  at  every  step.  In  fact,  the  very  idea  of 
energy  is  connected  with  the  existence  of  this  principle. 
We  first  discover  the  idea  in  the  work  of  the  philo- 
sophical mathematicians  who  established  the  founda- 
tions of  mechanics: — Newton,  Leibniz,  d'Alembert, 
and  Helmholtz ;  or  of  inductive  physicists  such  as 
Lord  Kelvin.  Its  experimental  proof,  sketched  by 
Marc  Seguin  and  R.  Mayer,  is  due  to  Colding  and 
Joule. 

It  is  Independent  of  the  Kinetic  Theory. — Mayer's 
law  states  that  energy  is  indestructible;  that  all 
phenomenality  is  nothing  but  a  transformation  of 
energy  from  one  form  to  another,  and  that  this 
transformation  takes  place  either  at  equal  values, 
or  rather,  at  a  certain  rate  of  equivalence.  This  is 
what  takes  place  when  thermal  energy  is  transformed 
into  mechanical  energy  (equivalent  425).  This  rate 
of  equivalence  is  fixed  by  the  researches  of  physicists 
for  each  category  of  energy. 

It  will  be  noticed  that  this  law  and  this  theory  of 
energy,  which  is  always  presented  by  authors  of 
elementary  books  as  a  consequence  of  the  kinetic 
theory,  is  quite  independent  of  it.  In  the  preceding 
lines  we  have  not  even  mentioned  its  name.  We 
have  not  assumed  that  all  phenomena  are  movements 
or  transformations  of  movements,  whether  sensible  or 
vibratory;  we  have  not  affirmed  that  what  was 
passing  from  one  phenomenal  determination  to 
another  was  the  vis  viva  of  the  motion,  as  is  the  case 


ENERGY   IX    GEXERAL.  QI 

in  the  impact  of  elastic  bodies.  No  doubt  the  kinetic 
theory-  affords  us  a  very  striking  image  of  these  truths 
which  are  independent  of  it;  but  it  may  be  false:  and 
the  theory  of  energy*  which  assumes  the  minimum  of 
possible  hypotheses  would  yet  be  true. 

//  contains  a  great  many  other  Principles. — 
The  principle  of  the  conservation  of  energy  contains 
a  large  number  of  the  most  general  principles  of 
science.  It  may  be  shown  without  much  difficulty 
that,  for  example,  it  contains  the  principle  of  the 
inertia  of  matter,  laid  down  by  Galileo  and  Descartes ; 
that  of  the  equality  of  action  and  reaction,  due  to 
Newton ;  and  even  that  of  the  conservation  of  matter. 
or  rather  of  mass,  due  to  Lavoisier.  And  finally,  it 
contains  the  experimental  law  of  equivalence  con- 
nected with  the  name  of  the  English  physicist  Joule, 
from  which  may  be  derived  the  Law  of  Hess  and  the 
principle  of  the  initial  and  final  states  which  we  owe 
to  Berthelot 

//  inrofats  the  Lav:  of  Equivalence : — Here  we  may- 
be content  with  noticing  that  the  law  of  the  conserva- 
tion of  energy  involves  the  existence  of  relations  of 
equivalence  between  the  different  varieties.  A  certain 
quantity*  of  a  given  energy,  measured,  as  we  have 
seen,  by*  the  product  of  two  factors,  is  equivalent  to  a 
certain  fixed  quantity  of  quite  a  different  form  of 
energy  into  which  it  may  be  converted.  The  laws 
which  govern  energetic  transformations  therefore  con- 
tain, from  both  the  qualitative  and  the  quantitative 
points  of  view,  all  the  connections  of  the  phenomena 
of  the  universe.  To  study  these  laws  in  their  detail  is 
the  task  that  physics  must  take  upon  itselt 

The  conversion  one  into  the  other  of  the  different 
forms  of  energy  by  means  of  equivalents  is  only  a 


Q2  LIFE    AND   DEATH. 

possibility.  It  is  subject,  in  fact,  to  all  sorts  of 
restrictions,  of  which  the  most  important  are  due  to 
the  second  principle. 

§  8.  CARNOT'S  PRINCIPLE.     ITS  GENERALITY. 

The  second  fundamental  principle  is  that  of  the 
transformations  of  equilibrium,  or  of  the  conditions 
of  reversibility,  or  again,  Carnot's  principle.  This 
principle,  which  first  assumed  a  concrete  form  in 
thermodynamics,  has  been  very  widely  extended.  It 
has  reached  a  degree  of  generality  such  that  contem- 
porary theoretical  physicists  such  as  Lord  Kelvin,  Le 
Chatelier,  etc.,  consider  it  the  universal  law  of 
physical,  mechanical,  and  chemical  equilibrium. 

Carnot's  principle  contains,  as  was  shown  by  G. 
Robin,  d'Alembert's  principle  of  virtual  velocities, 
and  according  to  physicists  of  to-day,  as  we  have  just 
remarked,  it  contains  the  laws  peculiar  to  physico- 
chemical  equilibrium.  The  application  of  this  prin- 
ciple gives  us  the  differential  equations  from  which 
are  derived  numerical  relations  between  the  different 
energies,  or  the  different  modalities  of  universal 
energy. 

Its  Character. — It  is  very  remarkable  that  we  can- 
not give  a  general  enunciation  of  this  principle  which 
by  its  revealing  power  has  changed  the  face  of 
physics.  This  is  because  it  is  less  a  law,  properly  so 
called,  than  a  method  or  manner  of  interpreting  the 
relations  of  the  different  forms  of  energy,  and  par- 
ticularly the  relations  of  heat  and  mechanical  energy. 

Conversion  of  Work  into  Heat  and  Vice-versa. — The 
conversion  of  work  into  heat  is  accomplished  without 
difficulty.  For  example,  the  hammering  of  a  piece  of 


ENERGY  IX   GENERAL.    '  93 

iron  on  an  anvil  may  bring  it  to  a  red  heat.  A  shell 
which  passes  through  an  armour  plate  is  heated,  and 
melts  and  volatilizes  the  metal  all  round  the  hole  it 
has  made.  By  utilizing  mechanical  action  under  the 
form  of  friction  all  energy  can  be  converted  into  heat 

The  inverse  transformation  of  heat  into  work,  on 
the  contrary,  cannot  be  complete.  The  best  motor 
that  we  can  think  of,  and  a  fortiori  the  best  we  can 
realize,  can  only  transfcrm  a  third  or  a  fourth  of  the 
heat  with  which  it  is  supplied. 

This  is  an  extremely  important  fact  It  is  of  in- 
calculable importance  to  natural  philosophy,  and  may 
be  ranked  among  the  greatest  discoveries. 

Higher  and  Degraded  Forms  of  Energy. — Of  these 
we  may  give  an  account  by  distinguishing  among  the 
forms  of  universal  energy  higher  forms,  and  lozwr  or 
degraded  forms.  Here  we  have  the  principle  of  the 
degradation  of  energy  on  its  trial,  and  it  may  be 
regarded  as  a  particular  aspect  of  the  second  principle 
of  energetics,  or  Carnot's  principle.  Mechanical 
energy  is  a  higher  form.  Thermal  energy  is  a  lower 
form,  a  degraded  form,  and  one  which  has  degrees  in 
its  degradation.  Higher  energy,  in  general,  may  be 
completely  converted  into  lower  energy;  for  example, 
work  into  heat :  the  slope  is  easy  to  descend,  but  it  is 
difficult  to  retrace  our  steps;  lower  energy  can  be 
only  partially  transformed  into  higher  energy,  and  the 
fraction  thus  utilizable  depends  upon  certain  con- 
ditions on  which  Carnot's  principle  has  thrown  con- 
siderable light 

Thus,  although  in  theory  the  thermal  energy  of  a 
body  may  have  its  equivalent  in  mechanical  energy, 
the  complete  transformation  is  only  realizable  from 
the  latter  to  the  former,  and  not  from  the  former  to 


94  UFE   AND   DEATH. 

the  latter.  This  is  due  to  a  condition  of  thermal 
energy  which  is  called  temperature.  The  same 
quantity  of  thermal  energy,  of  heat,  may  be  stored 
in  the  same  thermal  body  at  different  temperatures. 
If  this  quantity  of  thermal  energy  is  in  a  very  hot 
body  \ve  can  utilize  a  large  portion  of  it ;  if  it  is  in  a 
relatively  cold  body  we  can  only  convert  a  small 
portion  of  it  into  mechanical  work.  Thus  the  value 
of  energy, — i.e.,  its  capacity  of  being  converted  into 
a  higher  and  more  useful  form, — depends  on  tem- 
perature. 

The  Capacity  of  Conversion  depends  on  Temperature. 
— The  conversion  of  heat  into  work  assumes  two 
bodies  of  different  temperatures,  the  one  warm  and 
the  other  cold  ;  a  boiler  and  a  condenser.  Every 
thermal  machine  conveys  a  certain  amount  of  heat 
from  the  boiler  to  the  condenser,  and  what  is  not  thus 
carried  is  changed  into  work.  This  residue  is  only  a 
small  fraction,  a  quarter,  or  at  most  a  third  of  the 
heat  employed,  and  that,  too,  in  the  theoretically 
perfect  machine,  in  the  ideal  machine. 

This  output,  this  utilizable  fraction  depends  on  the 
fall  of  temperature  from  the  higher  to  the  lower  level, 
just  as  the  work  of  a  turbine  depends  on  the  height 
of  the  waterfall  which  passes  through  it.  But  it  also 
depends  on  the  conditions  of  this  fall,  on  the 
accessory  losses  from  radiation  and  conduction. 
However,  Carnot  has  shown  that  the  output  is  the 
same,  and  a  maximum  for  the  same  fall  of  temperature, 
whatever  be  the  working  agent  (steam,  hot  air,  etc.), 
and  whatever  be  the  machine — provided  that  this 
agent,  this  substance  which  works  is  not  exposed  to 
accessory  losses,  that  it  is  never  in  contact  with  a 
body  having  temperature  different  to  its  own — or 


ENERGY  IX   GEXERAL-  95 

ajain,  that  it  is  connected  only  with  bodies  im- 
permeable to  heat 

This  is  Carnot's  principle  in  one  of  its  concrete 
forms. 

A  machine  which  realizes  this  condition,  that  the 
agent  (steam,  alcohol,  ether)  is  in  relation,  at  all 
phases  of  its  function,  with  bodies  which  can  neither 
take  heat  from  it  nor  give  heat  to  it,  is  a  rercrsiblc 
machine.  Such  a  machine  is  perfect.  The  fraction 
of  heat  that  it  transforms  into  motion  is  constant ;  it 
is  a  maximum  ;  it  is  independent  of  the  motor,  of  its 
organs,  of  the  agent :  it  accurately  expresses  the 
transformability  of  the  heat  agent  into  a  mechanical 
agent  under  the  given  conditions. 

The  Degradation  and  Restoration  of  Energy. — The 
fraction  not  utilized,  that  which  is  carried  to  the 
condenser  at  a  lower  temperature,  is  degraded.  \l 
can  only  be  used  by  a  new  agent,  in  a  new  machine 
in  which  the  boiler  has  exactly  the  same  temperature 
as  the  condenser  in  the  first  machine,  and  the  new 
condenser  has  a  lower  temperature,  and  so  on.  The 
proportion  of  utilizable  energy  thus  goes  on  diminish- 
ing. Its  utilization  requires  conditions  more  and 
more  difficult  to  realize.  The  thermal  energy  loses  its 
potential  and  its  value,  and  is  further  and  further  de- 
graded as  its  temperature  approaches  that  of  the 
surrounding  medium. 

The  degraded  energy,  theoretically,  has  kept  its 
equivalent  value  but,  practically,  it  is  incapable  of 
conversion.  However,  it  is  shown  in  physics  that  it 
can  be  raised  and  re-established  at  its  initial  leveL 
But  for  that  purpose  another  energy  must  be  utilized 
and  degraded  for  its  benefit. 

The  End  of  the   Universe. — What   we  have  just 


96  LIFE   AND    DEATH. 

seen  with  respect  to  heat  and  motion  is  to  some 
degree  true  of  all  other  'forms  of  energy,  as  Lord 
Kelvin  has  shown.  The  principle  of  the  degradation 
of  energy  is  very  general.  Every  manifestation  of 
nature  is  an  energetic  transformation.  In  each  of 
these  transformations  there  is  a  degradation  of  energy — 
/>,  a  certain  fraction  is  lowered  and  becomes  less 
easily  transformable.  So  that  the  energy  of  the 
universe  is  more  and  more  degraded;  the  higher 
forms  are  lowered  to  the  thermal  form,  the  latter 
increasing  at  temperatures  which  become  more  and 
more  uniform.  The  end  of  the  universe,  from  this 
point  of  view,  would  then  be  unity  of  (thermal)  energy 
in  uniformity  of  temperature. 

Importance  of  the  Idea  of  Energy  in  Physiology, — 
I  have  said  that  the  application  of  Carnot's  principle 
furnished  numerical  relations  between  the  different 
energetic  transformations. 

The  science  of  living  beings  has  not  yet  reached 
that  point  of  development  at  which  it  is  possible  for 
us  to  obtain  its  numerical  relations.  However,  the 
consideration  of  energy  and  the  principle  of  conserva- 
tion has  altered  the  outlook  of  physiology  on  many 
questions  which  are  of  the  highest  importance. 

The  determination  of  the  sources  from  which  plants 
and  animals  draw  their  vital  energies;  the  mediate 
transformation  of  chemical  energy  into  animal  heat  in 
nutrition,  or  into  motion  in  muscular  contraction  ;  the 
chemical  evolution  of  foods ;  the  study  of  soluble 
ferments — all  these  questions  are  of  considerable 
importance  when  we  wish  to  understand  the 
mechanisms  of  life.  They  are  therefore  depart- 
ments of  physiological  energetics  in  which  great 
advances  have  already  been  made. 


CHAPTER    II. 

ENERGY   IN    BIOLOGY. 

§  i.  Energy  in  Living  Beings. — §  2.  The  First  Law  of  Biological 
Energetics: — All  Vital  Phenomena  are  Energetic  Trans- 
formations.— §  3.  Second  Law : — The  Origin  of  Vital 
Energy  is  in  Chemical  Energy.  Functional  Activity  and 
Destruction.—!  4.  Third  Law:— The  Final  Form  of 
Energetic  Transformation  in  the  Animal  is  Thermal 
Energy.  Heat  is  an  Excretum. 

THE  theory  of  energy  was  thought  of  and  utilized  in 
physiology  before  it  was  introduced  into  physics,  in 
which  it  has  exercised  such  an  extraordinary  influence. 
Robert  Mayer  was  a  physicist  and  a  doctor.  Helm- 
holtz  was  equally  at  home  in  physiology  and  in  physics. 
From  the  outset  both  had  seen  in  this  new  idea  a 
powerful  instrument  of  physiological  research.  The 
volume  in  which  Robert  Mayer  expounded,  in  1845, 
his  remarkable  views  on  organic  movement  in  relation 
to  nutrition,  and  Helmholtz'  commentary  leave  us  in 
no  doubt  in  this  respect.  The  essay  on  the  mechanical 
equivalent  of  heat,  of  a  more  particularly  physical 
character,  is  six  years  later  than  the  earlier  work. 

The   Relations   betiveen   Energetics   and  Biology. — 

The  theory  of  energy  is  therefore  only  returning  to 

its  cradle;  and  to  that  cradle  it  returns  with  all  the 

sanction  of  physical  proof,  as  the  most  general  theory 

97 


98  LIFE   AND    DEATH. 

ever  proposed  in  natural  philosophy,  and  the  theory 
least  encumbered  with  hypotheses.  It  reduces  all 
particular  laws  to  two  fundamental  principles — that 
of  the  conservation  of  energy,  which  contains  the 
principles  of  Galileo  and  Descartes,  of  Newton,  of 
Lavoisier,  Joule's  law,  Hess's  law,  and  Berthelot's 
principle  of  the  initial  and  final  states ;  and  also 
Carnot's  principle,  from  which  are  deduced  the  laws 
of  physico-chemical  and  chemical  equilibrium.  These 
two  principles  therefore  sum  up  the  whole  of  natural 
science.  They  express  the  necessary  relation  of  all 
the  phenomena  of  the  universe,  their  uninterrupted 
gentic  connection,  and  their  continuity. 

A  priori  there  would  be  little  likelihood  that  a 
doctrine,  so  universal  and  so  thoroughly  verified  in 
the  physical  world,  could  be  restricted,  and  thus 
be  useless  to  the  living  world.  Such  a  supposi- 
tion would  be  contrary  to  the  scientific  method,  which 
always  tends  to  the  generalization  and  the  explanation 
of  elementary  laws.  The  human  mind  has  always 
proceeded  thus :  it  has  applied  to  the  unknown 
order  of  living  phenomena  the  most  general  laws  of 
contemporary  physics. 

This  application  has  been  found  legitimate,  and  has 
been  justified  by  experiment  whenever  it  has  been  a 
question  of  the  laws  or  of  the  really  fundamental  or 
elementary  conditions  of  phenomena.  It  has,  on  the 
other  hand,  however,  been  unfortunate  when  it  has 
stopped  short  of  secondary  characteristics.  When  we 
now  concede  the  subjection  of  living  beings  to  these 
general  laws  of  energetics,  we  are  following  a 
traditional  method.  There  is  no  doubt  that  this 
application  is  legitimate,  and  that  experiment  will 
justify  it  a  posteriori. 


ENERGY   IX    BIOLOGY.  99 

I  will  therefore  grant,  as  a  provisional  postulate, 
the  consequences  of  which  will  have  to  be  ultimately 
justified,  that  the  Hying  and  inanimate  world  alike 
show  us  nothing  but  transformations  of  matter  and 
transformations  of  energy.  The  word  phenomenon 
will  have  no  other  signification,  whatever  be  the 
circumstances  under  which  the  phenomenon  occurs. 
The  varied  manifestations  which  translate  the  activity 
of  living  beings  thus  correspond  to  transformations  of 
energy,  to  conversions  of  one  form  into  another,  in 
conformity  with  the  rules  of  equivalence  laid  down  by 
the  physicists.  This  conception  may  be  formulated 
in  the  following  manner: — TIic  pJienomena  of  life  have 
t/ie  same  claim  to  be  energetic  metamorphoses  as  t/u 
other  phenomena  of  nature. 

This  postulate  is  the  foundation  of  biological 
energetics.  It  may  be  useful  to  give  some  ex- 
planation relative  to  the  signification,  the  origin,  and 
the  scope  of  this  statement. 

Biological  energetics  is  nothing  but  general  physi- 
ology reduced  to  the  principles  that  are  common  to  all 
the  physical  sciences.  Robert  Mayer  and  Helmholtz 
gave  the  best  description  of  this  science,  and  laid 
down  its  limits  by  defining  it  as  "  the  study  of  the 
phenomena  of  life  regarded  from  the  point  of  view 
of  energy." 

§  i.  ENERGY  AT  PLAY  IN  LIVING  BEINGS. 
COMMON  OR  PHYSICAL  ENERGIES.  VITAL 
ENERGIES. 

Our  first  object  will  be  to  define  and  to  enumerate  the 
energies  at  play  in  living  beings ;  to  determine  their 
more  or  less  easy  transformations  from  one  to  another, 


100  LIFE   AND    DEATH. 

to  bring  to  light  the  general  laws  which  govern  those 
transformations,  and  finally  to  apply  them  to  the 
detailed  study  of  phenomena.  This  programme  may 
be  divided  into  four  parts. 

In  the  physical  world  the  specific  forms  of  energy 
are  not  numerous.  When  we  have  mentioned 
mechanical,  chemical,  radiant  (thermal  and  photic) 
energies,  electrical  energy,  with  which  is  blended 
magnetic  energy,  we  have  exhausted  the  catalogue  of 
natural  agents. 

But  is  this  list  for  ever  closed  ?  Are  vital  energies 
comprised  in  this  list?  These  are  the  first  questions 
which  we  must  ask  ourselves. 

The  iatro-mechanical  school,  on  a  priori  grounds 
give  an  affirmative  answer.  No  doubt  there  are  in  the 
living  organism  many  manifestations  which  are  pure 
physical  manifestations  of  known  energies,  mechanical, 
chemical,  thermal,  etc.  But  are  all  the  manifestations 
of  the  living  being  of  this  order?  Are  they  all,  hence- 
forth, reducible  to  the  categories  and  varieties  of  energy 
which  are  investigated  in  physics  ?  This  is  the  claim 
of  the  mechanical  school.  But  the  claim  is  rash.  Our 
fundamental  postulate  affirms,  in  principle,  that  uni- 
versal energy  is  manifested  in  living  beings ;  but,  as  a 
matter  of  fact,  there  is  no  reason  for  the  assertion  that 
it  does  not  assume  particular  forms,  according  to  the 
circumstances  peculiar  to  the  conditions  under  which 
they  are  produced. 

These  special  forms  of  energy  manifested  in  the  con- 
ditions suitable  to  living  beings  would  swell  the  list 
drawn  up  by  the  physicists.  And  it  would  not  be  the 
first  instance  of  an  extension  of  this  kind.  The 
history  of  science  records  many  remarkable  cases. 
Scarcely  a  century  has  passed  since  we  first  heard  of 


ENERGY   IX    BIOLOGY.  IOI 

electrical  energy.  This  discovery  in  the  world  of 
energy,  which  took  place,  so  to  speak,  before  our 
very  eyes,  of  an  agent  which  plays  so  large  a  part 
in  nature,  clearly  leaves  the  door  open  to  other 
surprises. 

We  shall  therefore  concede  that  there  may  be 
other  forms  of  ejiergy  at  work  in  living  beings  than 
those  we  ajrgadyjcnow  in  the  physical  world.  This 
reservation  would  enable  us  to  discover  at  once  the 
essential  characteristics  by  which  vital  phenomena 
are  henceforth  reduced  to  universal  physics,  and 
the  purely  formal  differences  still  distinguishing 
them. 

If  there  arj  really  special  energies  in  living  beings, 
our  monistic  postulate  leads  us  to  assert  that  these 
energies  are  homogeneous  with  the  others,  and  that 
they  do  not  differ  from  them  more  than  they  differ 
among  themselves.  It  is  probable  that  some  day 
they  will  be  discovered  external  to  living  bodies,  if 
the  material  conditions  (which  it  is  always  possible  to 
imagine;  are  realized  externally  to  them.  And  if  we 
must  admit  that  the  peculiarity  of  the  medium  is 
such  that  these  forms  must  remain  indefinitely 
peculiar  to  living  beings,  we  may  assert  with  every 
confidence  that  these  special  energies  do  not  obey 
special  laws.  They  are  subject  to  the  two  funda- 
mental principles  of  Robert  Mayer  and  CarnoL 
They  are  exchanged  according  to  fixed  laws  with 
the  other  physical  forms  of  energies  at  present 
known. 

To  sum  up,  then,  we  must  establish  three  categories 
in  the  forms  of  energy  which  express  the  phenomena 
of  vitality. 

In  the  first  place,  most  of  these  energies  are  those 


IO2  LIFE    AND    DEATH. 

which  have  already  been  studied  and  recognized  in 
general  physics.  They  are  the  same  energies : 
chemical,  thermal,  mechanical,  with  their  char- 
acteristics of  mutability,  their  lists  of  equivalents, 
ami  their  actual  and  potential  states. 
I  In  the  second  place,  it  may  happen,  and  it  prob- 
ably will  happen,  as  it  happened  in  the  last  century 
in  the  case  of  electricity,  that  some  new  form  of 
energy  will  be  discovered  belonging  to  the  universal 
order  as  to  the  living  order.  This  will  be  a  conquest 
of  general  physics  as  well  as  of  biology. 

And  finally  we  may  rigorously  and  provisionally 
admit  a  last  category  of  vital  energies  properly  so 
called. 

It  is  difficult  to  give  much  precision  to  the  idea  of 
vital  energies  properly  so  called. 

It  will  be  easier  to  measure  them  by  means  of 
equivalents  than  to  indicate  their  nature.  Besides, 
this  is  the  ordinary  rule  in  the  case  of  physical  agents. 
We  can  measure  them,  although  we  know  not  what 
they  are. 

Characteristics  of  Vital  Energies. — We  see  why  we 
cannot  exhibit  with  precision,  a  priori^  the  nature  of 
vital  energies.  In  the  first  place,  they  are  expressed 
by  what  takes  place  in  the  tissues  in  activity,  and 
this  cannot  at  present  be  identified  with  the  known 
types  of  physical,  chemical,  and  mechanical  pheno- 
mena. This  is  a  first,  intrinsic  reason  for  not  being 
able  to  distinguish  them  readily,  since  what  takes 
place  is  not  distinguished  by  the  phenomenal  appear- 
ances to  which  we  are  accustomed. 

There  is  a  second,  intrinsic  reason.  These  vital 
phenomena  are  intermediary,  as  we  shall  see,  between 
manifestations  of  known  energies.  They  lie  between 


ENERGY   IN    BIOLOGY.  103 

a  chemical  phenomenon  which  always  precedes  them, 
and  a  thermal  phenomenon  which  always  follows 
them.  They  are  lost  sight  of,  as  it  were,  between 
manifestations  which  strike  our  attention.  Generally 
speaking,  intermediary  energies  often  escape  us 
even  in  physics.  Only  the  extreme  manifestations 
are  clearly  seen.  In  the  presence  of  the  organism 
we  are,  as  it  were,  in  electric  lighting  works  which 
are  run  by  a  fall  of  water,  and  at  first  we  only 
see  the  mechanical  energy  of  the  falling  water, 
of  the  turbine  and  dynamo  at  work,  and  the 
photic  energy  of  the  lamps  which  give  the  light. 
Electrical  energy,  an  intermediary,  which  has  only 
a  transient  existence,  does  not  impose  itself  on  our 
attention. 

And  so  vital  energies  for  this  twofold  reason,  in- 
trinsic and  extrinsic,  are  not  readily  apparent  To 
reveal  them,  the  careful  analysis  of  the  physiologists 
is  required.  They  are  acts,  in  most  cases  silent  and 
invisible,  which  we  should  scarcely  recognize  but  by 
their  effects,  after  they  have  terminated  in  familiar, 
phenomenal  forms.  This  is,  for  example,  what  goes 
on  in  the  muscle  in  process  of  shortening,  in  the  nerve 
carrying  the  nervous  influx,  in  the  secreting  gland. 
And  this  is  what  constitutes  the  different  forms  of 
energy  which  wre  call  vital  properties.  M.  Chauveau 
and  M.  Laulanie  use  the  phrase  physiological  u'ork 
to  distinguish  them.  Vital  energy  would  be  prefer- 
able. It  better  expresses  the  analogy  of  this  special 
form  with  the  other  forms  of  universal  energy;  it 
helps  us  better  to  understand  that  we  must  hence- 
forth consider  it  as  exchangeable  by  means  of 
equivalents  with  the  energies  of  the  physical  world 
just  as  they  are  exchangeable  one  with  another. 

8 


104  LIFE  AND  DEATH- 

§  2.  FIRST  LAW  OF  BIOLOGICAL  ENERGETICS. 

It  is  easy  to  understand,  after  these  remarks,  the 
significance  and  the  scope  of  this  assertion  which 
contains  the  first  principle  of  biological  energetics — 
namely,  that  the  phenomena  of  life  have  the  same 
claim  to  be  called  energetic  metamorphoses  as  the 
other  phenomena  of  nature. 

Irreversibility  of  Vital  Energies. — However,  there 
is  one  characteristic  of  vital  energies  which  deserves 
the  closest  attention.  Their  transformations  have  a 
direction  which  is  in  some  measure  inevitable.  They 
descend  a  slope  which  they  never  re-ascend.  They 
appear  to  be  irreversible.  Ostwald  has  rightly  in- 
sisted on  this  fundamental  characteristic,  which  no 
doubt  is  not  that  of  all  the  phenomena  of  the  living 
being  without  exception,  but  which  is  certainly  that  of 
the  most  essential  phenomena.  There  are  reversible 
phenomena  in  organisms  ;  there  are  energetic  trans- 
formations which  may  take  place  from  one  form  of 
energy  to  another,  or  vice  versa.  But  the  most 
characteristic  phenomena  of  vitality  do  not  act  in 
this  way.  We  shall  presently  see  that  most  functional 
physiological  acts  begin  with  chemical  and  end  with 
thermal  action.  The  series  of  energetic  transforma- 
tions takes  place  in  an  inevitable  direction,  from 
chemical  to  thermal  energy.  The  order  of  succession 
of  ordinary  energies  is  thus  determined  in  the  machine 
of  the  organism,  and  therefore  by  the  conditions  of 
the  machine.  \The  order  of  transformation  of  vital 
energies  is  still  more  rigorously  regulated,  and  the 
phenomena  of  life  evolve  from  childhood  to  ripened 
years,  and  thence  to  old  age,  without  a  possible 
returnA 


ENERGY  IN   BIOLOGY.  IO5 

The  laws  of  biological  energetics  are  three  in  num- 
ber. First  of  all,  there  is  the  fundamental  principle 
which  we  have  just  developed,  and  which  is,  so  to 
speak,  laid  down  a  priori;  and  there  are  two  other 
principles,  those  established  by  experiment  and 
summing-up,  as  it  were,  the  multitude  of  known 
physiological  effects.  Of  these  two  experimental 
laws,  one  refers  to  the  origin  and  the  other  to  the 
termination  of  tJu  energies  developed  in  living  beings. 

§  3.  SECOND  LAW  OF  BIOLOGICAL  ENERGETICS. 

The  Oigin  of  Vital  Energy. — Vital  energies  have 
their  origin  in  one  of  the  external  or  common  energies 
— not  in  any  one  we  choose,  as  might  be  supposed. 
but  in  one  only:  chemical  energy.  The  third  principle 
will  show  us  that  they  terminate  in  another  energy  or 
a  few  others,  also  completely  fixed. 

It  follows  that  the  phenomena  of  life  must  appear 
to  us  to  be  a  circulation  of  energy  which,  starting  from 
one  fixed  point  in  the  physical  world,  returns  to  that 
world  by  a  few  points,  also  fixed,  after  a  transient 
passage  through  the  animal  organism. 

Or  more  precisely,  it  is  a  transposition  from  the 
realm  of  matter  into  the  world  of  energy,  of  the  idea 
of  the  "vital  vortex  of  Cuvier  and  the  biologists. 
They  defined  life  by  its  most  constant  property — 
nutrition.  Nutrition  was  exactly  this  current  of 
matter  which  the  organism  obtains  from  without  by 
alimentation,  and  which  it  throws  out  again  by  ex- 
cretion ;  and  the  even  momentary  interruption  of 
which,  if  complete,  would  be  the  signal  of  death. 
The  cycle  of  energy  is  the  exact  counterpart  of 
this  cycle  of  matter. 


106  LIFE   AND   DEATH. 

The  second  truth  taught  us  by  general  physiology, 
a  truth  which  physiology  learned  from  experiment,  is 
enunciated  as  follows  :—^The  maintenance  of  life  con- 
sumes none  of  its  energy.  It  borrows  from  the  external 
world  all  the  energy  which  it  expends •,  and  borrows  it  in 
the  form  of  'potential  chemical  energy^}  This  is  a  trans- 
lation into  the  language  of  energetics  of  the  results 
acquired  in  animal  physiology  during  the  last  fifty  years. 
No  comment  is  needed  to  exhibit  the  importance  of 
such  a  truth.  It  reveals  the  origin  of  animal  activity. 
It  reveals  the  source  from  which  proceeds  that  energy 
which  at  some  moment  of  its  transformations  in  the 
animal  organism  will  be  a  vital  energy. 

The  prinmm  movens  of  vital  activity  is,  therefore, 
according  to  this  law,  the  chemical  energy  stored  up 
in  the  immediate  principles  of  the  organism. 

Let  us  try  to  follow,  for  a  moment,  this  energy 
through  the  organism  and  to  specify  the  circumstances 
of  its  transformations. 

Organic  Functional  Activity,  and  the  Destruction  of 
Reserve-stuff. — Let  us  suppose  then,  for  this  purpose, 
that  our  attention  is  directed  to  a  given  limited  part 
of  this  organism,  to  a  certain  tissue.  Let  us  seize 
it,  so  to  speak,  by  observation  at  a  given  moment, 
and  let  us  make  an  examination  of  the  functional 
activity  starting  from  this  conventional  moment. 
This  functional  activity,  like  all  other  vital  pheno- 
mena, will  be  the  result,  as  we  have  just  explained,  of 
a  transformation  of  the  potential  chemical  energy 
contained  in  the  materials  held  in  reserve  in  the 
tissue.  This  is  our  first  perceptible  fact.  This 
energy,  when  disengaged,  will  furnish  to  the  vital 
action  the  means  by  which  it  may  be  prolonged. 

There  is,  then,  a  functional  destruction.    There  is,  at 


ENERGY   IX    BIOLOGY.  J.OJ 

the  beginning  of  the  functional  process,  and  by  a 
necessary  effect  of  that  very  process,  a  liberation  of 
chemical  energy;  and  that  can  only  take  place  by  a 
decomposition  of  the  immediate  principles  of  the 
tissue,  or,  as  we  may  say,  by  a  destruction  of  organic 
material.  Claude  Bernard  insisted  on  this  considera- 
tion, that  the  vital  function  is  accompanied  by  a 
destruction  of  organic  material.  "  When  a  movement 
is  produced,  when  a  muscle  is  contracted,  when 
volition  and  sensibility  are  manifested,  when  thought 
is  exercised,  when  a  gland  secretes,  then  the  substance 
of  the  muscles,  of  the  nerves,  of  the  brain,  of  the 
glandular  tissue,  is  disorganized,  is  destroyed,  and  is 
consumed."  Energetics  enables  us  to  grasp  the 
deeply-seated  reason  of  this  coincidence  between 
chemical  destruction  and  the  functional  activity,  the 
existence  of  which  Claude  Bernard  intuitively  sus- 
pected. A  portion  of  organic  material  is  decomposed, 
is  chemically  simplified,  becomes  less  complex,  and 
loses  in  this  kind  of  descent  the  chemical  energy 
which  it  contained  in  its  potential  state.  It  is  this 
energy  which  becomes  the  very  texture  of  the  vital 
phenomenon. 

It  is  clear  that  the  reserve  of  energy  thus  expended 
must  be  replaced,  because  the  organism  remains  in 
equilibrium.  Alimentation  provides  for  this. 

How  does  it  provide  for  it?  This  is  a  question 
which  deserves  detailed  examination.  We  cannot 
incidentally  treat  it  in  full ;  we  can  only  indicate  its 
main  features. 

How  the  supply  of  Resene  Stuff  is  kept  tip. — We 
know  that  food  does  not  directly  replace  the  reserve 
of  energy  consumed  by  the  functional  activity.  It  is 
not  its  potential  chemical  energy  which  replaces, 


108  LIFE   AND    DEATH. 

purely  and  simply,  the  energy  brought  into  play, 
consumed,  or,  better  still,  transformed  in  the  active 
organ,  or  tissue.  Food  as  it  is  introduced,  inert  food, 
does  not,  in  fact,  take  up  its  place  as  it  z's,  without 
undergoing  changes  in  that  organ  and  that  tissue,  in 
order  to  restore  the  status  quo  ante. 

Before  building  up  the  tissue  it  will  have  undergone 
various  modifications  in  the  digestive  apparatus.  It 
will  have  also  undergone  changes  in  the  circulatory 
apparatus,  in  the  liver,  and  in  the  very  organ  we  are 
considering.  It  is  after  all  these  changes  that  assimila- 
tion takes  place.  It  will  find  its  place  and  will  have 
then  passed  into  the  state  of  reserve. 

The  food  digested,  modified,  and  finally  incorporated 
as  an  integral  part  in  the  tissue  in  which  it  will  be  ex- 
pended, is  therefore  in  a  new  state,  differing  more  or 
less  from  its  state  when  it  was  ingested.  It  is  a  part 
of  the  living  tissue  in  the  state  of  constitutive  reserve. 
Its  potential  chemical  energy  is  not  the  same  as  that 
of  the  food  introduced.  It  may  differ  from  it  very 
remarkably  in  consequence  of  sudden  alterations. 

We  do  not  know  for  certain  at  the  expense  of  what 
category  of  foods  this  or  that  given  organ  builds  up 
its  reserve  stuff.  There  is  a  belief,  for  instancej 
according  to  M.  Chauveau,  that  the  muscle  does  its 
work  at  the  expense  of  the  reserve  of  glycogen  which 
it  contains.  The  potential  chemical  energy  of  this 
substance  would  be  a  source  of  muscular  mechanical 
energy.  But  we  do  not  know  exactly  at  the  expense 
of  what  foods,  albumenoids,  fats,  or  carbohydrates 
the  muscle  builds  up  the  reserve  of  glycogen  expended 
during  its  contraction.  It  is  probable  that  it  builds  it 
up  at  the  expense  of  each  of  the  three  categories  after 
the  various  more  or  less  simple  alterations  undergone 


ENERGY  IN    BIOLOGY.  IOQ 

by  the  materials  in  the  digestive  tube,  the  blood,  the 
liver,  or  other  organs. 

This  building  up  of  reserve  stuff,  the  complement 
and  counterpart  of  functional  destruction,  is  not  chemi- 
cal synthesis.  It  is,  on  the  contrary,  generally,  and 
on  the  whole,  a  simplification  of  the  food  that  has 
been  introduced.  This  is  true,  at  least  as  far  as  the 
muscle  is  concerned.  However,  to  this  operation, 
Claude  Bernard  has  given  the  name  of  organizing 
syntJiesis,  but  the  phrase  is  not  a  happy  one.  But 
in  no  case  was  the  eminent  physiologist  deceived 
as  to  the  character  of  the  operation.  "  The  organ- 
izing synthesis,"  says  he,  "remains  internal,  silent, 
hidden  in  its  phenomenal  expression,  gathering 
together  noiselessly  the  materials  which  will  be 
expended." 

These  considerations  enable  us  to  understand  the 
existence  of  the  two  great  categories  into  which  the 
eminent  physiologist  divides  the  phenomena  of  animal 
life:  the  phenomena  of  the  destruction  of  reservc- 
stuff  correspond  ing  to  functional  facts — that  is  to  say 
expenditures  of  energy;  and  the  plastic  pJtenomena  of 
the  building-up  of  resen-cs  of  organic  regeneration,  cor- 
responding to  functional  repose — i.e.,  to  the  supply  of 
food  to  the  tissues. 

Distinction  between  Active  Protoplasm  and  Resen-e- 
stuff. — If  it  is  not  exactly  in  these  terms  that  Claude 
Bernard  formulated  this  fruitful  idea,  it  is  at  any 
rate  in  this  way  that  it  is  to  be  interpreted.  This 
can  be  done  by  giving  it  a  little  more  precision. 
We  apply  more  rigorously  than  that  great  physio- 
logist the  distinction  drawn  by  himself  between  really 
active  and  living  protoplasm  and  the  reserve-stuff 
which  it  prepares.  To  the  latter  is  restricted  the 


HO  LIFE    AND    DEATH. 

destruction  by  the  functional  activity  and  the  building 
up  by  repose. 

The  classification  of  Claude  Bernard  is  strictly  true 
for  reserve-stuff.  It  is  easy  to  criticize  the  wavering 
and,  as  it  were,  dimly  groping  expressions  in 
which  the  celebrated  physiologist  has  shrouded  his 
ideas.  The  old  adage  will  excuse  him:  Obscuritate 
rerum  verba  obscurantur.  In  the  depths  of  his  ignor- 
ance he  had  a  flash  of  genius ;  perhaps  he  did  not  find 
the  definitive  and,  as  it  were,  clearly-cut  formula  de- 
fining what  was  in  his  mind.  But,  in  this  respect,  he 
has  left  his  successors  an  easy  task. 

The  Law  of  Functional  Assimilation. — The  progress 
of  physiological  knowledge  compels  us  therefore  to 
distinguish  in  the  constitution  of  anatomical  elements 
two  parts — the  materials  of  reserve-stuff  w&  the  really 
active  and  living  protoplasm.  We  have  just  seen  how 
the  reserve-stuff  behaves,  alternately  destroyed  by 
functional  activity,  and  built  up  afterwards  by  the 
ingestion  of  food,  followed  by  the  operations  of  di- 
gestion, elaboration,  and  assimilation.  It  remains  to 
ask  how  this  really  living  and  protoplasmic  matter 
behaves.  Does  it  follow  the  same  law  ?  Is  it  de- 
stroyed during  the  functional  activity,  and  is  it  after- 
wards replaced?  As  to  this  we  can  express  no 
opinion.  M.  le  Dantec  fills  a  gap  in  our  knowledge, 
in  this  respect,  by  an  hypothesis.  He  assumes  that 
this  essentially  active  matter  grows  during  functional 
activity,  and  is  destroyed  during  repose.  This  is  what 
he  calls  the  law  of  functional  assimilation.  The 
protoplasm  would  therefore  behave  in  an  exactly 
contrary  manner  to  the  reserve-stuff.  It  will  be  its 
counterpart.  But  this  is  only  an  hypothesis  which, 
in  the  present  state  of  our  knowledge,  cannot  be 


ENERGY   IN    BIOLOGY.  Ill 

verified  by  experiment  We  are  at  liberty  to 
assert  either  that  the  protoplasm  increases  by 
functional  activity  or  that  it  is  destroyed.  Neither 
the  arguments  nor  the  objections  pro  or  con  have  any 
decisive  value.  The  facts  alleged  on  either  side  are 
capable  of  too  many  interpretations.1 

The  only  favourable  argument  (not  demonstrative) 
is  furnished  by  energetics.  It  is  this.  The  re-building 
of  the  protoplasm  is  not  like  the  organization  of  reserve- 
stuff^  a  slightly  complicated  or  even  simplified  pheno- 
menon, as  happens  in  the  case  of  the  reserve  of 
muscular  glycogen.  The  glycogen,  in  fact,  is  built  up 
at  the  expense  of  foods  chemically  more  complex. 
It  is,  on  the  contrary,  a  clearly  synthetic  pheno- 
menon, certainly  of  chemical  complexity,  since  it  ends 
in  building  up  the  active  protoplasm  which  is,  in  some 
measure,  of  the  highest  scale  of  complexity.  Its  for- 
mation at  the  expense  of  the  simplest  alimentary 
materials  requires,  therefore,  an  appreciable  quantity 
of  energy. 

The  assimilation  which  organizes  the  active  proto- 
plasm therefore  requires  energy  for  its  realization. 
Now,  at  the  moment  of  functional  activity,  and  by  a 
necessary  consequence  thereof,  the  chemical  destruc- 

1  The  reason  is  to  be  found  in  the  large  number  of  indeter- 
minates  in  the  problem  we  have  to  solve.  It  will  be  sufficient 
to  enumerate  them  :  the  two  substances  which  exist  in  the 
anatomical  element,  protoplasm  and  reserve-stuff,  to  which 
are  attributed  contrary  roles ;  the  two  conditions  attributable 
to  the  protoplasm,  of  manifested  or  latent  activity  ;  the  faculty 
possessed  by  both  of  being  prolonged  for  an  indeterminate 
period,  and  of  encroaching  each  on  its  protagonist  when  its 
existence  is  at  stake.  Here  are  more  elements  than  are  neces- 
sary to  explain  the  positive  or  negative  results  of  all  the 
experiments  in  the  world. 


112  LIFE    AND    DEATH. 

tion  or  simplification  of  the  substance  of  reserve  takes 
place.  Here  is  something  that  meets  the  case,  and 
we  may  note  the  coincidence.  It  does  not  mean  that 
the  disposable  energy  is  really  used  to  increase  the 
protoplasm,  nor  that  the  protoplasm  itself  is  thereby 
increased.  It  merely  signifies  that  the  wherewithal 
exists  to  provide  for  that  increase  if  it  takes  place. 

It  is  therefore  possible  that  the  active  protoplasm 
follows  the  law  of  functional  assimilation ;  but  it  is 
certain  that  the  reserve-stuff  follows  the  law  laid  down 
by  Claude  Bernard. 

All  these  considerations  definitely  result  in  the 
confirmation  of  this  second  law  of  general  physiology, 
according  to  which  all  vital  energies  are  borrowed 
from  the  potential  chemical  energy  of  the  reserve-stuff 
of  alimentary  origin. 


§  4.  THE  THIRD  LAW  OF  BIOLOGICAL  ENERGETICS. 

The  third  law  of  biological  energetics  is  also  drawn 
from  experiment.  It  relates  no  longer  to  the  point  of 
departure  of  the  cycle  of  animal  energy,  but  to  its 
final  position.  Tlie  energetic  transformations  of  tJie 
animal  end  in  tliermal  energy. 

This  is  the  most  novel  part  of  the  theory,  and,  if  we 
may  say  so,  that  least  understood  by  physiologists 
themselves.  The  energy  resulting  from  the  chemical 
potential  of  food,  having  passed  through  the  organism 
(or  simply  through  the  organ  which  we  are  considering 
in  action),  and  having  given  rise  to  phenomenal  ap- 
pearances more  or  less  diversified,  more  or  less  dim  or 
clear,  obscure  or  obvious,  which  are  the  characteristic 
or  still  irreducible  manifestations  of  vitality,  finally 


EXERGY   IX   BIOLOGY.  113 

returns  to  the  physical  world.  This  return  takes 
place  (with  certain  exceptions  which  will  be  presently 
indicated)  under  the  ultimate  form  of  thermal  energy. 
This  we  are  taught  by  experiment.  The  phenomena 
of  functional  activity  are  exothermal. 

Real  vital  phenomena  thus  lie  between  the  chemical 
energy  which  gives  rise  to  them,  and  the  thermal 
phenomena  to  which  they  in  their  turn  give  rise.  The 
place  of  the  vital  fact  in  the  cycle  of  universal  energy 
is  therefore  completely  determined.  This  conclusion 
is  of  the  utmost  importance  to  biology.  It  may  be 
expressed  in  a  concise  formula  which  sums  up  in  a 
few  words  all  that  natural  philosophy  can  teach  as  to 
energetics  applied  to  living  beings.  "  Vital  energy  is 
a  transformation  of  chemical  energy  into  thermal 
energy." 

Exceptions. — There  are  some  exceptions  to  the 
rigour  of  this  statement,  but  they  are  not  many  in 
number.  We  must  first  of  all  remark  that  it  applies 
to  animal  life  alone. 

In  the  rase  of  vegetables,  looked  at  as  a  whole,  the 
law  must  be  modified.  Their  vital  energy  has  another 
origin,  and  another  final  form.  Instead  of  being  the 
destroyers  of  chemical  potential  energy,  they  are  its 
creators.  They  build  up  by  means  of  the  inert  and 
simple  materials  afforded  them  by  the  atmosphere 
and  the  soil,  the  immediate  principles  by  which  their 
cells  are  filled.  Their  vital  functional  activity  forms  by 
synthesis  of  the  reserves,  carbo-hydrates  (sugars  and 
starches),  fats,  albuminoid  nitrogenous  materials — that 
is  to  say,  the  same  three  principal  categories  of  foods 
as  those  used  by  ?nifiraSsL 

And  to  return  to  the  latter,  it  should  be  observed 
that  thermal  energy  is  not  the  only  final  form  of  vital 


114  LIFE    AND    DEATH. 

energy,  as  this  dogmatic  statement  would  have  it 
supposed.  It  is  only  the  principle  of  the  final  forms. 
The  cycle  of  energy  occasionally  terminates  in 
mechanical  energy  (phenomena  of  motion)  and  in 
a  less  degree  in  other  energies ;  such  as,  for  example, 
the  electrical  energy  produced  by  the  functional  activity 
of  the  nerves  and  muscles  in  all  animals,  or  in  the 
functional  activity  of  special  organs  in  rays,  torpedo- 
fish,  and  the  malapterurus  electricus,  or  finally,  in  the 
photic  energy  of  phosphorescent  animals.  But  these 
are  secondary  facts. 

Heat  is  an  Excretuni. — The  third  principle  of  bio- 
logical energetics  may  be  therefore  thus  enunciated  : — 
Vital  energy  in  its  final  form  becomes  thermal  energy. 
This  principle  teaches  us  that  if  chemical  energy  is 
the  primitive  generating  form  of  vital  energies, 
thermal  energy  is  the  form  of  waste,  of  emunctory, 
the  degraded  form  as  the  physicists  would  say.  Heat 
is  in  the  dynamical  order  an  excretion  of  animal 
life,  as  urea,  carbonic  acid  and  water,  are  excreta  in 
the  substantial  order.  By  a  false  interpretation  of 
the  principle  of  the  mechanical  equivalence  of  heat,  or 
through  ignorance  of  Carnot's  principle,  certain 
physiologists  have  fallen  into  error  when  they  still 
speak  of  the  transformation  of  heat  into  motion  or  into 
into  electricity  in  the  animal  organism.  Heat  is  trans- 
formed into  nothing  in  the  animal  organism.  It  is  dis- 
sipated. Its  utility  arises  not  from  its  energetic  value, 
but  from  the  part  it  plays  as  a  primer  in  the  chemical 
reactions,  as  has  been  explained  with  reference  to  the 
general  characteristics  of  chemical  energy. 

The  Effect  of  Energetics  on  our  Knowledge  of  the 
Relations  of  the  Universe. — The  consequences  of  these 
principles  of  energetic  physiology,  which  give  us  so 


ENERGY   IN    BIOLOGY.  115 

much  and  which  are  so  clear,  are  of  the  greatest 
importance  from  the  practical  as  well  as  from  the 
theoretical  point  of  view. 

In  the  first  place,  they  show  us  the  position  and  the 
rank  of  the  phenomena  of  life  in  the  universe  as  a 
whole.  They  throw  fresh  light  on  the  noble  harmony 
of  the  animal  and  vegetable  kingdoms  which  Priestley, 
Ingenhousz,  Senebier.  and  the  chemical  school  of  the 
beginning  of  the  nineteenth  century  discovered,  and 
which  was  expounded  by  Dumas  with  incomparable 
lucidity  and  brilliance.  Energetics  is  expressed  in  a 
line.  "The  animal  world  expends  the  energy  ac- 
cumulated by  the  vegetable  world."1  It  extends  these 
views  beyond  the  living  kingdoms.  It  shows  how  the 
vegetable  world  itself  draws  its  activity  from  the 
energy  radiated  by  the  sun,  and  how  animals  restore 
it  again,  in  dissipated  heat,  to  the  cosmic  medium. 
It  extends  the  harmony  of  the  two  kingdoms  to  the 
whole  of  nature.  The  new  science  makes  of  the 
whole  universe  one  connected  system. 

From  a  more  limited  point  of  view,  and  so  that  we 
may  not  restrict  ourselves  to  a  consideration  of  the 
domain  of  animal  physiology,  the  laws  of  energetics 
sum  up  and  explain  a  multitude  of  facts  and  of 
experimental  laws — for  example,  the  law  of  the  inter- 
mittence  of  physiological  activity,  the  facts  of  fatigue, 
the  role  and  the  general  principles  of  alimentation, 
and  the  conditions  of  muscular  contraction. 


CHAPTER    III. 

ALIMENTARY   ENERGETICS. 

Various  Problems  of  Alimentation.  §  i.  Food  the  source  of 
Energy  and  Matter.  The  two  forms  of  Energy  afforded  by 
Food — Vital  Energy,  Thermal  Energy.  Food  the  source 
of  Heat.  The  role  of  Heat.— §  2.  Measure  of  the  output  of 
Energy — by  the  Calometric  Method — by  the  Chemical 
Method. — §  3.  The  regular  type  of  Food,  Biothermogenic, 
and  the  irregular  type,  Thermogenic. — §  4.  Food  considered 
as  the  source  of  Heat.  The  Law  of  Surfaces.  The  limits 
of  Isodynamics.— §  5,  Plastic  role  of  Food.  Preponderance 
of  Nitrogenous  Foods, 

AMONG  the  problems  on  which  energetics  has 
thrown  a  vivid  light  we  have  mentioned  alimentation, 
muscular  contraction,  and,  more  general  still,  the 
intermittence  of  vital  functional  activity.  We  shall 
begin  with  the  study  of  alimentation. 

The  Different  Problems  of  Alimentation. — What  is  a 
food?  In  what  does  alimentation  consist?  The 
dictionary  of  the  Academic  will  give  us  our  first 
answer.  It  tells  us  that  the  word  food  is  applied  to 
"every  kind  of  matter,  whatever  may  be  its  nature, 
which  habitually  serves  or  may  serve  for  nutrition." 
This  is  very  well  put,  but  here  again  we  must  know 
what  nutrition  is,  and  that  is  not  a  simple  matter;  in 
fact,  it  practically  means  whatever  is  usually  placed 
on  the  table  in  a  civilized  and  polished  society.  But 
116 


ALIMENTARY   ENERGETICS.  1 17 

it  is  just  the  profound  reasons  for  this  traditional 
practice  that  we  are  trying  to  discover. 

The  problem  of  alimentation  may  be  looked  at  in  a 
thousand  ways.  It  is  culinary,  no  doubt,  and  gas- 
tronomic; but  it  is  also  economical  and  social, 
agricultural,  fiscal,  hygienic,  medical,  and  even  moral. 
But  first  and  foremost,  it  is  physiological.  It  com- 
prises and  assumes  the  knowledge  of  the  general 
composition  of  foods,  of  their  transformations  in  the 
digestive  apparatus,  and  their  comparative  utility  in 
the  maintenance  and  the  sound  functional  activity 
of  the  organism.  To  this  first  group  of  subjects  for 
our  discussion  are  attached  others  relating  to  the 
effects  of  inanition,  of  insufficient  alimentation,  and  of 
over-feeding.  And  in  order  to  throw  light  on  all 
these  aspects  of  the  problem  of  alimentation,  we  have 
to  lay  bare  the  most  intimate  and  delicate  reactions  by 
which  the  organism  is  maintained  and  recruited,  and, 
in  the  words  of  a  celebrated  physiologist,  "  to  pene- 
trate into  the  kitchen  of  vital  phenomena."  And  here 
neither  Apicius,  nor  Brillat-Savarin,  nor  Berchoux, 
nor  the  moralists,  nor  the  economists  are  of  any  use 
to  us  as  guides.  We  must  appeal  to  the  scientists, 
who,  following  the  example  of  Lavoisier,  Berzelius, 
Regnault,  and  Liebig,  have  applied  to  the  study  of 
living  beings  the  resources  of  general  science,  and 
have  thus  founded  cJiemical  biology. 

This  branch  of  science  developed  considerably  in 
the  second  half  of  the  nineteenth  century.  It  has  now 
its  methods,  its  technique,  its  chairs  at  the  universities, 
its  laboratories,  and  its  literature.  It  has  particularly 
applied  itself  to  the  study  of  the  "  material  changes" 
or  the  metabolism  of  living  beings,  and  with  that 
object  in  view  it  has  done  two  things  In  the  first 


Il8  LIFE    AND    DEATH. 

place,  it  has  determined  the  composition  of  the 
constituent  materials  of  the  organism;  then  analyzing 
qualitatively  and  quantitatively  all  that  penetrates  into 
that  organism  in  a  given  time — that  is  to  say,  all  the 
alimentary  or  respiratory  ingesta,  and  all  that  issues 
from  the  organism,  i.e.,  all  the  excreta,  all  the  egesta, 
— it  has  drawn  up  nutritive  balance  sheets,  corre- 
sponding to  the  various  conditions  of  life,  whether 
naturally  or  artificially  created.  And  thus  we  can 
determine  the  alimentary  regimes  which  give  too 
much,  and  which  give  too  little,  and  which  finally 
restore  equilibrium. 

We  do  not  propose  to  give  a  detailed  account  of 
this  scientific  movement.  This  may  be  done  in  mono- 
graphs. All  we  wish  to  indicate  here  is  the  most 
general  result  of  these  laborious  researches — that  is 
to  say,  the  laws  and  the  doctrines  which  are  derived 
from  them,  and  the  theories  to  which  they  have  given 
birth.  It  is  by  this  alone  that  they  are  brought  into 
relation  with  general  science,  and  may  therefore 
interest  the  reader.  The  facts  of  detail  are  never 
lacking  to  the  historian ;  it  is  more  profitable  to  show 
the  movement  of  ideas.  The  theories  of  alimentation 
bring  into  conflict  very  different  conceptions  of 
the  vital  functional  activity.  And  here  we  find  a 
confused  medley  of  opinions  on  which  it  is  not  without 
interest  to  endeavour  to  throw  some  light. 

§  i.  FOOD,  A  SOURCE  OF  ENERGY  AND  MATTER. 

Definitions  of  Food. — Before  the  introduction  into 
physiology  of  the  notion  of  energy,  no  one  had 
succeeded  in  giving  an  exact  idea  and  a  precise 
definition  of  food  and  alimentation.  Every  physio- 


ALIMENTARY  EXERGETICS.  IIQ 

legist  and  medical  man  who  attempted  it  had  failed, 
and  this  for  various  reasons. 

The  general  cause  of  this  failure  was  that  most  de- 
finitions, popular  or  technical,  interposed  the  condition 
that  the  food  must  be  introduced  into  the  digestive 
apparatus.  "It  is,"  said  they,  *  a  substance  which 
when  introduced  into  the  digestive  tube  undergoes, 
etc.,  etc"  But  plants  draw  food  from  the  soil,  and 
they  possess  no  digestive  apparatus;  many  animals 
have  no  intestinal  tube;  and  in  the  case  of  certain 
rotifera,  the  females  possess  a  digestive  apparatus, 
while  the  males  have  none.  Nevertheless  all  animals 
feed. 

On  the  other  hand,  there  are  other  substances  than 
those  which  use  the  digestive  tract  for  the  purpose  of 
entering  the  organism,  and  which  are  eminently  useful 
or  necessary  to  the  maintenance  of  life.  In  par- 
ticular we  may  mention  oxygen. 

The  distinctive  feature  of  food  is  its  utility — when 
conveniently  introduced  or  employed — to  the  living 
being.  Claude  Bernard's  definition  is  this: — A  sub- 
stance taken  in  the  external  medium  "  necessary  for  the 
maintenance  of  the  phenomena  of  the  healthy  organism 
and  for  the  reparation  of  the  losses  it  constantly 
suffers."  "  A  substance  which  supplies  an  element 
necessary  for  the  constitution  of  the  organism,  or 
which  diminishes  its  disintegration?  (stored-up  food); 
this  is  the  definition  of  C  Voit,  the  German  physio- 
logist. M.  Dnclaux  says,  in  his  turn,  but  in  far  too 
general  terms,  that  it  is  a  substance  which  contributes 
to  assure  the  sound  functional  activity  of  any  of  the 
organs  of  the  living  being.  None  of  these  ways  of 
describing  food  gives  a  complete  idea. 

Food,  tlu  Source  of  Energy  and  Matter. — The  inter- 

9 


120  LIFE    AND    DEATH. 

vention  of  the  notion  of  energy  enables  us  more 
completely  to  understand  the  true  nature  of  food. 
We  must,  in  fact,  have  recourse  to  the  energetic  con- 
ception if  we  desire  to  take  into  account  all  that  the 
organism  requires  from  food.  It  not  only  requires 
matter,  but  also,  and  most  important  of  all,  energy. 

Investigators  so  far  concentrated  their  thoughts  ex- 
clusively on  the  necessity  of  a  supply  of  matter — that 
is  to  say,  they  only  looked  upon  one  side  of  the 
problem.  The  living  body  presents,  at  each  of  its 
points,  an  uninterrupted  series  of  disintegrations  and 
reconstitutions,  the  materials  being  supplied  from 
without  by  alimentation,  and  rejected  by  excretion. 
Cuvier  gave  to  this  unceasing  circulation  of  ambient 
matter  throughout  the  vital  world  the  name  of  vital 
vortex,  and  he  rightly  saw  in  it  the  characteristic  of 
nutrition,  and  the  distinctive  feature  of  life. 

This  idea  of  the  cycle  of  matter  has  been  com- 
pleted in  our  own  time  by  that  of  the  cycle  of 
energy.  All  the  phenomena  of  the  universe,  and 
therefore  those  of  life,  are  conceived  of  as  energetic 
transformations.  We  now  look  at  them  in  their  relation- 
ship instead  of  considering  them  individually  as  of  old. 
Each  has  an  antecedent  and  a  consequent  unity  with 
which  it  is  connected  in  magnitude  by  the  law  of 
equivalents  taught  us  by  contemporary  physics.  And 
thus  we  may  conceive  of  their  succession  as  the 
cycle  of  a  kind  of  indestructible  agent,  which  changes 
only  apparently,  or  assumes  another  form  as  it  passes 
from  one  to  the  other,  but  its  magnitude  remains 
unaltered.  This  is  energy.  Thus,  in  the  living  being 
there  is  not  only  a  circulation  of  matter,  but  also  a 
circulation  of  energy. 

The  most  general  result  of  research  in  physiological 


ALIMENTARY   ENERGETICS.  121 

chemistry  from  the  time  of  Lavoisier  down  to  our  own 
day  has  been  to  teach  us  that  tlie  antecedent  of  the 
vital  phenomenon  is  always  a  cJumical  pJienomenon. 
The  vital  energies  are  derived  from  the  potential 
chemical  energy  accumulated  in  the  immediate  con- 
stituent principles  of  the  organism.  In  the  same  way 
tfu  consequent  pJienomenon  of  tJte  vital  pJienomenon  is  in 
general  a  tliermal  phenomenon.  The  final  form  of 
vital  energy  is  thermal  energy.  These  three  assertions 
as  to  the  nature,  the  origin,  and  the  final  form  of  vital 
phenomena  constitute  the  three  fundamental  prin- 
ciples, the  three  laws,  of  biological  energetics. 

Food,  a  Source  of  Heat.  It  is  not  qua  source  of  Jieat 
tttatfood  is  the  source  of  vital  energy. — The  place  of 
vital  energy  in  the  cycle  of  universal  energy  is  com- 
pletely determined.  It  lies  between  the  chemical 
energy  which  is  its  generating  form  and  the  thermal 
energy  which  is  its  form  of  disappearance,  of  break- 
down, the  "degraded  form,"  as  the  physicists  say. 
Hence  we  have  a  result  which  can  be  immediately 
applied  in  the  theory  of  food — namely,  that  heat  is  in 
the  dynamical  order  an  excretum  of  the  animal  life 
rejected  by  the  living  being,  just  as  in  the  substantial 
order,  urea,  carbonic  acid  and  water,  are  the  materials 
used  up  and  again  rejected  by  it  We  therefore  must 
not  think  of  the  transformation  in  the  animal  organ- 
ism of  heat  into  vital  energy,  as  certain  physiologists 
always  do.  Nor  must  we  think,  with  Beclard,  of  its 
transformation  into  muscular  movement ;  or,  as  others 
have  maintained,  into  animal  electricity.  This  is  not 
only  an  error  of  doctrine  but  an  error  of  fact  It 
proceeds  from  a  false  interpretation  of  the  principle  of 
the  mechanical  equivalent  of  heat  and  a  misunder- 
standing of  Carnot's  principle.  Thermal  energy  does 


122  LIFE    AND    DEATH. 

not  repeat  the  course  of  the  energetic  flux  in  the 
animal  organism.  The  heat  is  not  transformed  into 
anything.  It  is  simply  dissipated. 

The  Part  played  by  Animal  Heat  as  a  Condition  of 
Physiological  Manifestations. — Does  this  mean  that 
heat  is  useless  to  life  in  the  very  beings  in  which  it  is 
most  abundantly  produced — i.e.,  in  man  and  in  the 
warm-blooded  vertebrates  ?  So  far  from  this  being  so, 
it  is  necessary  to  life.  But  its  utility  has  a  peculiar 
character  which  must  neither  be  misunderstood  nor 
exaggerated.  It  is  not  transformed  into  chemical 
or  vital  reactions,  but  merely  creates  for  them  a 
favourable  condition. 

According  to  the  first  principle  of  energetics,  for 
the  vital  fact  to  be  derived  from  the  thermal  fact,  the 
heat  must  be  preliminarily  transformed  into  chemical 
energy,  since  chemical  energy  is  necessarily  an  ante- 
cedent and  generating  form  of  vital  energy.  Now 
this  regressive  transformation  is  impossible  according 
to  the  current  theories  of  general  physics.  The  part 
played  by  heat  in  the  act  of  chemical  combination  is 
that  of  a  primer  to  the  reaction.  It  consists  in  placing 
the  reacting  bodies,  by  changing  their  state  or  by 
modifying  their  temperature,  in  the  condition  in  which 
they  ought  to  be  for  the  chemical  forces  to  come  into 
play.  For  example,  in  the  combination  of  hydrogen 
and  oxygen  by  setting  light  to  an  explosive  mixture, 
heat  only  acts  as  a  primer  to  the  phenomenon,  because 
the  two  gases  which  are  passive  at  ordinary  tempera- 
tures, require  to  be  raised  to  400°  C.  before  chemical 
affinity  comes  into  play.  And  so  it  is  with  the 
reactions  which  go  on  in  the  organism.  They  have 
a  maximum  temperature,  and  the  part  played  by 
animal  heat  is  to  furnish  them  with  it. 


ALIMENTARY   ENERGETICS.  123 

It  follows  that  heat  intervenes  in  animal  life  in  two 
capacities — first  and  foremost  as  uceretum,  or  end  of 
the  vital  phenomenon,  of  physiological -a.~ork\  and  on 
the  other  hand,  as  a  condition  or  primer  of  die  chemical 
reactions  of  the  organism ;  and  generally,  as  a  favour- 
able condition  for  the  appearance  of  the  physiological 
manifestations  of  living  matter.  Thus,  it  is  not 
dissipated  in  sheer  waste. 

I  was  led  to  adopt  these  views  some  years  ago 
from  certain  experiments  on  the  role  played  in  food  by 
alcohol  I  did  not  then  know  that  they  had  already 
been  expressed  by  one  of  the  masters  of  contemporary 
physiology,  M.  A.  Chauveau,  and  that  they  were 
related  in  his  mind  to  a  series  of  conceptions  and  of 
researches  of  great  interest,  in  the  development  of 
which  I  have  since  then  taken  a  share. 

Two  Forms  of  Energy  supplied  to  Animals  bj  Feed. 
—To  say  that  food  is  simultaneously  a  supply  of 
energy  and  a  supply  of  matter,  is  really  to  express  in 
a  single  sentence  the  fundamental  conception  of 
biology,  in  virtue  of  which  life  brings  into  play  no 
substratum  or  characteristic  dynamism.  According 
to  this,  the  living  being  appears  to  us  as  the 
seat  of  an  incessant  circulation  of  matter  and  energy, 
starting  from  the  external  world  and  returning 
to  it  All  food  is  nothing  but  this  matter  and  this 
energy.  All  its  characteristics,  our  views  as  to  its 
role,  its  evolution,  all  the  rules  of  alimentation  are 
simple  consequences  of  this  principle,  interpreted  by 
the  light  of  energetics. 

And  first  of  all,  let  as  ask  what  forms  of  energy  are 
afforded  by  food?  It  is  easy  to  see  that  there  are 
two — food  is  essentially  a  source  of  chemical  energy ; 
and  secondarily  and  accessorily,  it  is  a  source  of  heat 


124  LIFE    AND    DEATH. 

Chemical  energy  is  the  only  energy,  according  to  the 
second  law  of  energetics,  which  may  be  transformed 
into  vital  energy.  It  is  true  at  any  rate  for  animals ; 
for  in  plants  it  is  otherwise.  There  the  vital  cycle  has 
neither  the  same  point  of  departure  nor  the  same  final 
position.  The  circulation  of  energy  does  not  take 
place  in  the  same  manner. 

On  the  other  hand,  and  this  we  are  taught  by  the 
third  law,  energy  brought  into  play  in  vital  pheno- 
mena is  finally  liberated  and  restored  to  the  physical 
world  in  the  form  of  heat.  We  have  just  said  that 
this  release  of  heat  is  employed  in  raising  the  tem- 
perature of  the  living  being.  It  is  animal  heat. 

Thus  there  are  two  forms  of  energy  supplied  by 
food,  chemical  and  thermal. 

It  must  be  added  that  these  are  not  the  only  forms, 
but  the  principal,  and  by  far  the  most  important  It  is 
not  absolutely  true  that  heat  is  the  only  outcome  of  the 
vital  cycle.  It  is  only  so  in  the  subject  in  repose,  con- 
tented to  live  idly  without  doing  external  mechanical 
work,  without  lifting  a  tool  or  a  weight,  even  that  of  its 
own  body.  And  again,  speaking  in  this  way,  we  neglect 
all  the  movements  and  all  the  mechanical  work  which 
is  done  without  exercise  of  the  volition,  by  the  beating 
of  the  heart  and  of  the  arteries,  the  movements  of 
respiration,  and  the  contractions  of  the  digestive  tube. 

Mechanical  work  is,  in  fact,  another  possible  termi- 
nation of  the  cycle  of  energy.  But  there  is  no 
longer  anything  necessary  or  inevitable  in  this,  since 
motion  and  the  use  of  force  are  in  a  certain  measure 
subordinated  to  the  capricious  volition  of  the  animal.1 

1  There  is  another  reason  why  the  role  of  mechanical  energy, 
compared  with  that  of  thermal  energy,  is  reduced,  in  the  partition 
of  afferent,  alimentary  energy — at  least,  in  animals  which  have  not 


ALIMENTARY  ENERGETICS.  125 

At  other  times,  again,  it  is  an  electrical  phenomenon 
which  terminates  the  vital  cycle,  and  it  is,  in  fact,  in 
this  way  that  things  happen  in  the  functional  activity 
of  the  nerves  and  muscles  in  all  animals,  and  in  the 
functional  activity  of  the  electrical  organ  in  fish, 
such  as  the  ray  and  the  torpedo.  Finally,  the  ter- 
mination may  be  a  photic  phenomenon,  and  this  is 
what  happens  in  phosphorescent  animals. 

It  is  idle  to  diminish  the  power  of  these  principles 
by  proceeding  to  enumerate  the  whole  of  the  ex- 
ceptions to  their  validity.  We  know  perfectly  well 
that  there  are  no  absolute  principles  in  nature.  Let 
us  say,  then,  that  the  energy  which  temporarily 
animates  the  living  being  is  furnished  to  it  by  the 
external  world  under  the  exclusive  form  of  potential 
chemical  energy;  but  that,  if  there  is  only  one  door  of 
entry,  there  are  two  exits.  It  may  return  to  the  ex- 
ternal world  in  the  principal  form  of  thermal  energy 
and  in  the  accessory  form  of  mechanical  energy. 

§  2.  MEASUREMENT  OF  THE  SUPPLY  OF 
ALIMENTARY  ENERGY. 

Calorinutric  Method. — From  what  has  preceded  it 
is  clear  that  if  the  energetic  flux  which  circulates 
through  the  animal  emerges,  in  toto,  in  the  state  of 
heat,  the  measurement  of  this  heat  becomes  the 

to  do  excessive  work.  The  unit  of  heat,  the  Calorie,  is  equivalent 
to  425  unite  of  work — /^L,  to  425  kilogrammetres.  In  the  animal 
at  rest,  the  number  of  kilogrammetres  representing  the  different 
quantities  of  work  done  is  small,  the  number  of  corresponding 
Calories  is  425  times  smaller.  It  becomes  almost  negligeable  in 
comparison  with  the  considerable  number  of  Calories  dissipated 
in  the  form  of  heat. 


126  "LIFE    AND    DEATH. 

measurement  of  the  vital  energy  itself,  for  the  origin 
of  which  we  must  go  back  to  the  food.  If  the  flux  is 
divided  into  two  currents,  mechanical  and  thermal, 
they  must  both  be  measured  and  the  sum  of  their 
values  taken.  If  the  animal  does  not  produce  me- 
chanical work,  and  all  ends  in  heat,  we  have  only  to 
capture,  by  means  of  a  calorimeter,  this  energetic  flux 
as  it  emerges,  and  thus  measure  in  magnitude  and 
numerically  the  energy  in  motion  in  the  living  being. 
Physiologists  use  for  this  purpose  various  types  of 
apparatus.  Lavoisier  and  Laplace  used  an  ice  calori- 
meter— that  is  to  say,  a  block  of  ice  in  which  they 
shut  up  a  small  animal,  such  as  a  guinea-pig;  they 
then  measured  its  thermal  production  by  the  quantity 
of  ice  it  caused  to  melt.  In  one  of  their  experiments, 
for  instance,  they  found  that  a  guinea-pig  had  melted 
341  grammes  of  ice  in  the  space  of  ten  hours,  and  had 
therefore  set  free  27  Calories. 

But  since  those  days  more  perfect  instruments  have 
been  invented.  M.  d'Arsonval  employed  an  air  calori- 
meter, which  is  nothing  but  a  differential  thermometer 
very  ingeniously  arranged,  and  giving  an  automatic 
record.  Messrs.  Rosenthal,  Richet,  Him  and  Kauf- 
mann,  and  Lefevre  have  used  more  or  less  simplified 
or  complicated  air  calorimeters.  Others,  following 
the  example  of  Dulong  and  Despretz,  have  used 
calorimeters  of  air  and  mercury,  or  with  Liebermester, 
VVinternitz,  and  J.  Lefevre  (of  Havre),  have  had 
recourse  to  baths.  Here,  then,  there  is  a  considerable 
movement  of  research  which  has  led  to  the  discovery 
of  very  interesting  facts. 

Measurement  of  t/te  Supply  of  Alimentary  Energy 
by  the  CJiemical  MetJiod. — We  may  again  reach  our 
result  in  another  way.  Instead  of  surprising  the  cur- 


ALIMENTARY   ENERGETICS.  I2~ 

rent  of  energy  as  it  emerges  and  in  the  form  of 
heat,  we  may  try  and  capture  it  at  its  entry  in  the 
form  of  potential  chemical  energy. 

The  evaluation  of  potential  chemical  energy  may 
be  effected  with  the  same  unit  of  measurement  as  the 
preceding — that  is  to  say,  the  Calorie.  If  we  consider 
man  and  mammals,  for  example,  we  know  that  there 
is  only  apparently  an  infinite  variety  in  their  foods. 
We  may  say  that  they  feed  on  only  three  substances. 
It  is  a  very  remarkable  fact  that  all  the  complexity 
and  multiplicity  of  foods,  fruits,  grains,  leaves,  animal 
fi«qffc  and  vegetable  products  of  which  use  is  made, 
reduce  to  so  great  a  simplicity  and  uniformity,  that  all 
these  substances  are  of  three  types  only:  albuminoids, 
such  as  albumen  or  white  of  egg — foods  of  animal 
origin  or  varieties  of  albumen ;  carbo-hydrates,  which 
are  more  or  less  disguised  varieties  of  sugar;  and 
finally,  fats. 

Here,  then,  from  the  chemical  point  of  view,  leaving 
out  certain  mineral  substances,  are  the  principal 
categories  of  alimentary  substances,  Here,  with  the 
oxygen  that  is  brought  in  by  respiration,  is  every- 
thing that  penetrates  the  organism. 

And  now,  what  comes  out  of  the  organism  ?  Three 
things  only,  water,  carbonic  acid,  and  urea.  But  the 
former  are  the  products  of  the  combustion  of  the 
latter.  If  we  consider  an  adult  organism  in  perfect 
equilibrium,  which  varies  throughout  the  experiment 
neither  in  weight  nor  in  composition,  we  may  say  that 
the  receipts  balance  the  expenditure.  Albumen,  sugar, 
fat,  plus  the  oxygen  brought  in,  balance  quantitatively 
the  water,  carbonic  acid,  and  urea  expelled.  Things 
happen,  in  fact,  as  if  the  foods  of  the  three  categories 
were  burned  up  more  or  less  completely  by  the  oxygen. 


128  LIFE   AND    DEATH. 

It  is  this  combustion  that  we  have  known  since  the 
days  of  Lavoisier  to  be  the  source  of  animal  heat. 
We  can  easily  determine  the  quantity  of  heat  left  by 
albumen  passing  into  the  state  of  urea,  and  by  the 
starch,  the  sugars,  and  the  fats  reduced  to  the  state  of 
water  and  carbonic  acid.  This  quantity  of  heat  does 
not  depend  on  the  variety  of  the  unknown  inter- 
mediary products  which  have  been  formed  in  the 
organism.  Berthelot  has  shown  that  this  quantity  of 
heat  which  measures  the  chemical  energy  liberated  by 
these  substances  is  identical  with  the  quantity  ob- 
tained by  burning  the  sugar  and  the  fats  in  a  chemical 
apparatus,  in  a  calorimetric  bomb,  until  we  get  carbonic 
acid  and  water,  and  by  burning  albumen  till  we  get 
urea.  This  result  is  a  consequence  of  Berthelot's 
principle  of  initial  and  final  states.  The  liberated 
heat  only  depends  on  the  initial  and  final  states,  and 
not  on  the  intermediary  states.  The  heat  left  in  the 
economy  by  the  food  being  the  same  as  that  left  in 
the  calorimetric  bomb,  it  is  easy  for  the  chemist  to 
determine  it.  It  has  thus  been  discovered  that  one 
gramme  of  albumen  produces  4.8  Calories,  one  gramme 
of  sugar  4.2  Calories,  and  one  gramme  of  fat  9.4 
Calories.  We  thus  gather  what  a  given  ration — a  mix- 
ture in  certain  proportions  of  these  different  kinds  of 
foods — supplies  to  the  organism  and  what  energy 
it  gives  it,  measured  in  Calories. 

The  calculation  may  be  carried  out  to  a  high  degree 
of  accuracy  if,  instead  of  confining  ourselves  to  the 
broad  features  of  the  problem,  we  enter  into  rigorous 
detail.  It  is  only,  in  fact,  approximately  that  we  have 
reduced  all  foods  to  albumen,  sugar,  and  fat,  and  all 
excreta  to  water,  carbonic  acid,  and  urea. 

The    reality  is  a   little   more  complicated.     There 


ALIMENTARY   ENERGETICS.  I2Q 

are  varieties  of  albumen,  carbo-hydrates,  and  fatty 
bodies,  the  heats  of  combustion  of  which  in  the 
organism  oscillate  in  the  neighbourhood  of  the  num- 
bers 4.8,  4.2,  and  9.4.  Each  of  these  bodies  has  been 
individually  examined,  and  numerical  tables  have 
been  drawn  up  by  Berthelot,  Rubner,  Stohmann,  Van 
Noorden,  etc.  The  tables  exhibit  the  thermal  value 
or  energetic  value  of  very  different  kinds  of  foods. 

In  our  climate,  the  adult  average  man,  doing  no 
laborious  work,  daily  consumes  a  maintenance  ration 
composed,  as  a  rule,  of  100  grammes  of  albuminoids, 
49  grammes  of  fats,  and  403  grammes  of  carbo- 
hydrates. This  ration  has  an  energetic  value  of  2,600 
Calories. 

It  is  therefore,  thanks  to  the  victories  won  in  the 
field  of  thermo-chemistry,  and  to  the  principles  laid 
down  since  1864  by  M.  Berthelot,  that  this  second 
method  of  attack  on  nutritive  dynamism  has  been 
rendered  possible.  Physiologists,  by  the  aid  of  these 
methods,  have  drawn  up  balance-sheets  of  energy  for 
living  beings  just  as  they  had  previously  established 
balance-sheets  of  matter. 

Now,  it  is  precisely  researches  of  this  kind  that  we 
have  indicated  here  as  a  consequence  of  biological 
energetics,  which  in  reality  have  helped  to  build  up 
that  principle.  These  researches  have  shown  us  that, 
in  conformity  with  the  principles  of  tJiermodynamics, 
there  was  not,  in  fact,  in  the  organism,  any  trans- 
formation of  heat  into  mechanical  work,  as  the 
physiologists  for  a  short  time  supposed,  on  the 
authority  of  Berthelot  With  the  help  of  our  theory 
this  mistake  is  no  longer  possible.  The  doctrine  of 
energetics  shows  us  in  fact  the  current  of  energy 
dividing  itself,  as  it  issues  from  the  living  being,  into 


130  LIFE   AND   DEATH. 

two  divergent  branches,  the  one  thermal  and  the 
other  mechanical,  external  the  one  to  the  other 
although  both  issuing  from  the  same  common  trunk, 
and  having  between  them  no  relation  but  this,  that 
the  sum  of  their  discharges  represents  the  total  of  the 
energy  in  motion.  Let  us  now  translate  these  very 
simple  notions  into  the  more  or  less  barbarous  jargon 
in  use  in  physiology.  We  shall  be  convinced  as  we 
go  on  of  the  truth  of  the  saying  of  Buffon,  that  "the 
language  of  science  is  more  difficult  to  learn  than  the 
science  itself."  We  shall  say,  then,  that  chemical 
energy,  that  the  unit  of  weight  of  the  food  which  may 
be  placed  in  the  organism,  constitutes  the  alimentary 
potential,  the  energetic  value  of  this  substance,  its 
dynamogenic power.  It  is  measured  in  units  of  heat, 
in  Calories,  which  the  substance  may  leave  in  the 
organism.  The  evaluation  is  made  according  to  the 
principles  of  thermo-chemistry,  by  means  of  the 
numerical  tables  of  Berthelot,  Rubner,  and  Stohmann. 
The  same  number  also  expresses  the  thermogenic 
power,  virtual  or  theoretical,  of  the  alimentary  sub- 
stance. This  energy  being  destined  to  be  transformed 
into  "vital  energies  (Chauveau's  pJiysiological  work, 
pJiysiological  energy),  the  dynamogenic  or  thermogenic 
value  of  the  food  is  at  the  same  time  its  biogenetic 
value.  Two  weights  of  different  foods  which  supply 
the  organism  with  the  same  number  of  Calories, — i.e. 
for  which  these  numerical  values  are  the  same, — will  be 
called  isodynamic  or  isodynamogenic,  isobiogenetic,  iso- 
energetic  weights.  They  will  be  equivalent  from  the 
point  of  view  of  their  alimentary  value.  And  finally, 
if,  as  is  usually  the  case,  the  cycle  of  energy  ends  in 
the  production  of  heat,  the  food  which  has  been 
utilized  for  this  purpose  has  a  real  tliennogenic  value, 


ALIMENTARY   ENERGETICS.  131 

identical  with  its  theoretical  thermogenic  value.  In 
this  case  it  might  be  determined  experimentally  by 
direct  calorimetry,  measuring  the  heat  produced  by 
the  animal  supposed  absolutely  unchanged  and  iden- 
tical before  and  after  the  consumption  of  the  food. 


§  3.  DIFFERENT  TYPES  OF  FOODS.  THE  REGULAR, 
BlOTHERMOGENIC  TYPE  AND  THE  IRREGULAR, 
THERMOGENIC  TYPE. 

Food  is  a  source  of  thermal  energy  for  the  organ- 
ism because  it  is  decomposed  within  it,  and  undergoes 
within  it  a  chemical  degradation.  Physiological 
chemistry  tells  us  that  whatever  be  the  manner  in 
which  it  is  broken  up,  it  always  results  in  the  same 
body  and  always  sets  free  the  same  quantity  of  heat. 
But  if  the  point  of  departure  and  the  point  of  arrival 
are  the  same,  it  is  possible  that  the  path  pursued  is 
not  constantly  identical.  For  example,  one  gramme 
of  fat  will  always  give  the  same  quantity  of  heat, 
94  Calories,  and  will  always  come  to  its  final  state 
of  carbonic  acid  and  water ;  but  from  the  fat  to 
the  mixture  of  carbonic  acid  gas  and  water  there 
are  many  different  intermediaries.  In  a  word  we 
get  the  conception  of  varied  cycles  of  alimentary 
evolutions. 

From  the  point  of  view  of  the  heat  produced  it  has 
just  been  said  that  these  cycles  are  equivalent  But 
are  they  equivalent  from  the  vital  point  of  view? 
This  is  an  essential  question. 

Let  us  imagine  the  most  ordinary  alternative. 
Food  passes  from  the  natural  to  the  final  state  after 
being  incorporated  with  the  elements  of  the  tissues, 


132  LIFE    AND    DEATH. 

and  after  having  taken  part  in  the  vital  operations. 
The  chemical  potential '  only  passes  into  thermal 
energy  after  having  passed  through  a  certain  inter- 
mediary phase  of  vital  energy.  This  is  the  normal 
case,  the  regular  type  of  alimentary  evolution.  It  may 
be  said  in  this  case  that  the  food  has  fulfilled  the 
whole  of  its  function,  it  has  served  for  the  vital 
functional  activity  before  producing  heat.  It  has 
been  biothermogenic. 

The  irregular  or  pure  tJiermogenic  type. — And  now 
let  us  conceive  of  the  most  simple  irregular  or 
aberrant  type.  Food  passes  from  the  initial  to  the 
final  state  without  incorporation  in  the  living  cells  of 
the  organism,  and  without  taking  part  in  the  vital 
functional  activity.  It  remains  confined  in  the  blood 
and  the  circulating  liquids,  but  it  undergoes  in  the 
end,  however,  the  same  molecular  disintegration  as 
before,  and  sets  free  the  same  quantity  of  heat. 
Its  chemical  energy  changes  at  once  into  thermal 
energy.  Food  is  a  pure  thermogen.  It  has  fulfilled 
only  one  part  of  its  work.  It  has  been  of  slight 
vital  utility. 

Does  this  ever  occur  in  reality?  Are  there  foods 
which  would  be  only  pure  tJiermogens — that  is  to 
say,  which  would  not  in  reality  be  incorporated  with 
the  living  anatomical  elements,  which  would  form  no 
part  of  them  either  in  a  state  of  provisory  constituents 
of  the  living  protoplasm,  or  in  the  state  of  reserve- 
stuff;  which  would  remain  in  the  internal  medium,  in 
the  blood  and  the  lymph,  and  would  there  undergo 
their  chemical  evolution?  Or  again,  if  the  whole  of 
the  food  does  not  escape  assimilation,  would  it  be 
possible  for  part  to  escape  it  ?  Would  it  be  possible 
for  one  part  of  the  same  alimentary  substance  to  be 


ALIMENTARY    ENERGETICS.  133 

incorporated,  and  for  the  rest  to  be  kept  in  the  blood 
or  the  lymph,  in  the  circulating  liquids  ad  limina 
corporis,  so  to  speak  ?  In  other  words,  can  the  same 
food  be  according  to  circumstances  a  biotJiermogen  or 
a  pure  thermogen?  Some  physiologists — Pick  of 
Wurzburg,  for  instance — have  claimed  that  this  is 
really  the  case  for  most  nitrogenous  elements,  carbo- 
hydrates, and  fats;  all  would  be  capable  of  evolving 
according  to  the  two  types.  On  the  other  hand,  Zuntz 
and  von  Mering  have  absolutely  denied  the  existence 
of  the  aberrant  or  pure  thermogenic  type.  No  sub- 
stances would  be  directly  decomposed  in  the  organic 
liquids  apart  from  the  functional  intervention  of  the 
histological  elements.  Finally,  other  authors  teach 
that  there  is  a  small  number  of  alimentary  substances 
which  thus  undergoes  direct  combustion,  and  among 
them  is  alcohol. 

Liebig's  Superfluous  Consumption. — Liebig's  theory 
of  superfluous  consumption  and  Voit's  theory  of  the 
circulating  albumen  assert  that  the  proteid  foods 
undergo  partial  direct  combustion  in  the  blood  vessels. 
The  organism  only  incorporates  what  is  necessary 
for  physiological  requirements.  As  for  the  surplus 
of  the  food  that  is  offered  it,  it  accepts  it,  and,  so 
to  speak,  squanders  it;  it  burns  it  directly;  and 
we  have  a  "sumptuary"  consumption,  consumption 
de  luxe. 

In  this  connection  arose  a  celebrated  discussion 
which  still  divides  physiologists.  If  we  disen- 
gage the  essential  body  of  the  discussion  from  all 
that  envelops  it,  we  see  that  it  is  fundamentally  a 
question  of  deciding  whether  a  food  always  follows  the 
same  evolution  whatever  the  circumstances  may  be, 
and  particularly  when  it  is  introduced  in  great  excess. 


134  LIFE    AND    DEATH. 

Liebig  thought  that  the  superabundant  part,  escaping 
the  ordinary  process,  was  destroyed  by  direct  com- 
bustion. He  affirmed,  for  instance,  that  nitrogenous 
substances  in  excess  were  directly  burned  in  the  blood 
instead  of  passing  through  their  usual  cycle  of  vital 
operations.  We  might  express  the  same  idea  by 
saying  that  they  then  undergo  an  accelerated 
evolution.  Instead  of  passing  through  the  blood  in 
the  anatomical  element,  to  return  in  the  dismem- 
bered form  from  the  anatomical  element  to  the  blood, 
their  breaking  up  takes  place  in  the  blood  itself. 
They  save  a  displacement,  and  therefore  in  reality 
remain  external  to  the  construction  of  the  living 
edifice.  Their  energy,  crossing  the  intermediary  vital 
stage,  passes  with  a  leap  from  the  chemical  to  the 
thermal  form.  Liebig's  doctrine  reduced  to  this 
fundamental  idea  deserved  to  survive,  but  mistakes 
in  minor  details  involved  its  ruin. 

Voifs  Circulating  Albumen. — A  few  years  later 
C.  Voit,  a  celebrated  physiological  chemist  of  Munich, 
revived  it  in  a  more  extravagant  form.  He  held 
that  almost  the  whole  of  the  albuminoid  element 
is  burned  directly  in  the  blood.  He  interpreted 
certain  experiments  on  the  utilization  of  nitro- 
genous foods  by  imagining  that  these  substances 
when  introduced  into  the  blood  were  divided  as  a 
result  of  digestion  into  two  parts:  the  one  very  small, 
which  was  incorporated  with  the  living  elements,  and 
passed  into  the  stage  of  organized  albumen,  the  other, 
corresponding  to  the  greater  part  of  the  alimentary 
albumen,  remained  mingled  with  the  blood  and 
lymph,  and  was  subjected  in  this  medium  to  direct 
combustion.  This  was  circulating  albumen.  In  this 
theory  the  tissues  are  almost  stable  ;  the  organic 


ALIMENTARY  ENERGETICS.  135 

liquids  alone  are  subjected  to  oxydizing  transforma- 
tions, to  nutritive  metabolism.  The  accelerated 
evolution,  which  Liebig  considered  as  an  exceptional 
case,  was  to  C.  Voit  the  rule. 

Current  Ideas  as  to  the  R&U  of  Foods. — The  ideas 
of  to-day  are  not  those  of  Voit ;  but  they  do  not. 
however,  differ  from  them  essentially.  We  no  longer 
admit  that  the  greater  part  of  the  ingested  and 
digested  albumen  remains  confined  in  the  circulating 
medium  external  to  the  anatomical  elements.  It  is 
held,  with  Pfliiger  and  the  school  of  Bonn,  that  it 
penetrates  the  anatomical  element  and  is  incorpor- 
ated in  it ;  but  in  agreement  with  Voit  it  is  believed 
that  a  very  small  part  is  assimilated  to  the  really 
living  matter,  to  the  protoplasm  properly'  so  called  : 
the  greater  part  is  deposited  in  the  cellular  element 
as  reserve-stuff.  The  material,  properly  so  called,  of 
the  living  machine  does  not  undergo  destruction  and 
reparation  as  extensively  as  our  predecessors  supposed. 
There  is  no  need  for  great  reparation.  On  the  con- 
trary, the  physiological  activity  consumes  to  a  great 
extent  the  reserve-stuff.  And  the  greater  part  of 
the  food,  after  having  undergone  suitable  elabora- 
tion, serves  to  replace  the  reserve-stuff  destroyed 
in  each  anatomical  element  by  the  vital  functional 
activity. 

Experimental  Facts.  —  Among  the  facts  which 
brought  physiologists  of  the  school  of  Voit  to  believe 
that  most  foods  do  not  get  beyond  the  internal 
medium,  there  is  one  which  may  well  be  mentioned 
here.  It  has  been  observed  that  the  consumption  of 
oxygen  in  respiration  increases  notably  (about  a  fifth 
of  its  value)  immediately  after  a  meal  What  does 
this  mean  ?  The  interval  is  too  short  for  the  digested 

10 


136  LIFE   AND   DEATH. 

alimentary  substances  to  have  been  elaborated  and 
incorporated  in  the  living  cells.  It  is  supposed  that 
an  appreciable  time  is  required  for  this  complete 
assimilation.  The  products  of  alimentary  digestion 
are  therefore  in  all  probability  still  in  the  blood,  and 
in  the  interstitial  liquids  in  communication  with  it 
The  increase  of  oxygen  consumed  would  show  that  a 
considerable  portion  of  these  nutritive  substances 
absorbed  and  passed  into  the  blood  would  be  oxy- 
dized  and  then  and  there  destroyed.  But  this 
interpretation,  however  probable  it  may  be,  does  not 
really  fit  in  with  the  facts  in  such  a  way  that  we  may 
consider  it  as  proved.  Certain  experiments  by  Zuntz 
and  Mering  are  opposed  to  the  idea  that  combustion 
in  the  blood  is  easy.  These  physiologists  injected 
certain  oxydizable  substances  into  the  vessels  without 
being  able  to  detect  any  instantaneous  oxidation. 
It  is  only  fair  to  add  that  against  these  fruitless 
attempts  other  more  fortunate  experiments  may  be 
quoted. 

Category  of  Purely  TJiennogenic  Foods ;  with  Ac- 
celerated Evolution.  Alcohol.  Acids  of  Fruits. — 
The  accelerated  evolution  of  foods — an  evolution 
which  takes  place  in  the  blood,  that  is  to  say  outside 
the  really  living  elements — remains,  therefore,  very 
uncertain  as  far  as  ordinary  food  is  concerned.  It 
has  been  thought  that  it  was  a  little  less  uncertain 
as  far  as  the  special  category  of  alcohol,  acids  of 
fruits,  and  glycerine  is  concerned. 

Some  authors  consider  these  bodies  as  pure 
thermogens.  When  alcohol  is  ingested  in  moder- 
ate doses,  they  say  that  about  a  tenth  of  the 
quantity  absorbed  becomes  fixed  in  the  living  tissues; 
the  rest  is  "circulating  alcohol."  It  is  oxidized 


ALIMENTARY  ENERGETICS.  ±37 

directly  in  the  blood  and  in  the  lymph,  without  inter- 
vening in  the  vital  functions  other  than  by  the  heat 
it  produces.  From  the  point  of  view  of  the  energetic 
theory  these  are  not  real  foods,  because  their  potential 
energy  is  not  transformed  into  any  kind  of  vital 
energy,  but  passes  at  once  to  the  thermal  form.  On 
the  other  hand,  other  physiologists  look  upon  alcohol 
as  really  a  food.  According  to  them  everything  is 
called  a  food  which  is  transformed  in  the  organism 
with  the  production  of  heat ;  and  they  measure  the 
nutritive  value  of  a  substance  by  the  number  of 
Calories  it  can  give  up  to  the  organism.  So  that 
alcohol  would  be  a  better  food  than  carbohydrated 
and  nitrogenous  substances.  A  definite  quantity  of 
alcohol,  a  gramme  for  instance,  is  equivalent  from 
the  thermal  point  of  view  to  1.66  grammes  of  sugar, 
1.44  °f  albumen,  or  0.73  of  fat.  These  quantities 
would  be  iset/jrxamif. 

Experiment  has  not  entirely  decided  for  or  against 
this  theory.  However,  the  first  tests  have  not  been 
very  favourable  to  it.  The  researches  of  C.  von 
Noorden  and  his  pupils,  Stammreich  and  Miura,  have 
clearly  and  directly  established  that  alcohol  cannot 
be  substituted  in  a  maintenance  ration  for  an  exactly 
isodynamic  quantity  of  carbohydrates.  If  the  sub- 
stitution is  effected,  a  ration  only  just  capable  of 
maintaining  the  organism  in  equilibrium  becomes  in- 
sufficient. The  animal  decreases  in  weight.  It  loses 
more  nitrogenous  matter  than  it  can  recover  from 
its  diet,  and  this  situation  cannot  be  sustained  for 
long.  On  the  other  hand,  the  celebrated  researches 
of  the  American  physiologist,  A I  water,  would  plead, 
on  the  contrary,  in  favour  of  almost  isodynamic  sub- 
stitution. Finally,  Duclaux  has  shown  that  alcohol 


I3&  LIFE   AND   DEATH. 

is  a  real  food,  biothermogenic  for  certain  vegetable 
organisms.  But  urea  is  also  a  food  for  micrococcus 
urece.  It  does  not  follow  that  it  is  a  food  for  mam- 
mals. We  have  not  reached  the  solution  yet — adJiuc 
sub  judice. 

Conclusion  :  The  Energetic  Character  oj  Food. — To 
sum  up  we  have  confined  ourselves,  in  what  has  been 
said,  to  the  consideration  of  a  single  character  of 
food,  and  really  the  most  essential,  its  energetic 
character.  Food  must  furnish  energy  to  the  organism, 
and  for  that  purpose  it  is  decomposed  and  broken  up 
within  it,  and  issues  from  it  simplified.  It  is  thus, 
for  instance,  that  the  fats,  which  from  the  chemical 
point  of  view  are  complicated  molecular  edifices, 
escape  in  the  form  of  carbonic  acid  and  water.  And 
so  it  is  with  carbo-hydrates,  starchy  and  sugary 
substances.  This  is  because  these  compounds 
descend  to  a  lower  degree  of  complexity  during  their 
passage  through  the  organism,  and  by  this  drop,  as  it 
were,  they  get  rid  of  the  chemical  energy  which  they 
contained  in  the  potential  state.  Thermo-chemistry 
enables  us  to  deduce  from  the  comparison  of  the 
initial  and  final  states  the  value  of  the  energy 
absorbed  by  the  living  being.  This  energetic,  dynamo- 
genie  or  thermogenic  value,  thus  gives  a  measure  of 
the  alimentary  capacity  of  the  substance.  A  gramme 
of  fat,  for  instance,  gives  to  the  organism  a  quantity 
of  energy  equivalent  to  9.4  Calories ;  the  thermo- 
genic value  of  the  albumenoids  is  4.8  Calories. 
The  thermogenic  or  thermal  value  of  carbohydrates 
is  less  than  4.7  calories.  This  being  so,  we  under- 
stand why  the  animal  is  nourished  by  foods  which 
are  products  very  high  in  the  scale  of  chemical 
complexity. 


ALIMENTARY  ENERGETICS-  139 

|  4.  FOOD  CONSIDERED  EXCLUSIVELY  AS 
SOURCE  OF  HEAT. 

We  have  seen  that  food  is,  in  the  first  place,  a 
source  of  ckfmical  emergj ;  and,  in  the  second  place, 
a  source  of  vital  cmfrgy — finally,  and  consequently,  a 
source  of  thermal  energy.  It  is  this  last  point  of 
view  which  has  exclusively  struck  the  attention  of 
certain  physiologists,  and  hence  has  arisen  a  peculiar 
manner  of  conceiving  the  role  of  food.  It  consists  in 
looking  on  food  as  a  source  of  thermal  energy. 

This  conception  is  easily  applied  to  warm-blooded 
animals,  but  to  them  exclusively — and  this  is  where 
it  first  fails.  The  animal  is  wanner  than  the  environ- 
ment in  general  It  is  constantly  giving  out  heat  to 
it  To  repair  this  loss  of  heat  it  takes  in  food  in 
exact  proportion  to  the  loss  it  sustains,  When  it  is  a 
question  of  cold-blooded  vertebrates,,  which  live  in 
water  and  in  most  cases  have  an  internal  tem- 
perature which  is  not  distinguishable  from  that  of 
the  environment,  we  see  less  clearly  the  thermal  rdle 
of  food.  It  seems  then  that  the  production  of  heat 
is  an  episodic  phenomenon,  not  existing  for  itselt 

However  that  may  be,  food  is  in  the  second  pHace 
a  source  of  thermal  energy  for  the  organism.  Can  it 
be  said,  inversely,  that  every  substance  which  we  in- 
troduce into  the  economy,  and  which  is  there  broken 
up  and  gives  off  heat,  is  a  food  ?  This  is  a  moot 
point.  We  dealt  just  now  with  purely  thennogenic 
foods.  However,  most  physiologists  are  inclined  to 
give  a  positive  answer.  In  their  eyes  the  idea  of  food 
cannot  be  considered  apart  from  the  fact  of  die  pro- 
duction of  heat.  They  take  the  effect  for  the 


140  LIFE   AND   DEATH. 

cause.  To  these  physiologists  everything  ingested  is 
called  food,  if  it  gives  off  heat  within  the  body. 

To  be  heated  by  food  is,  indeed,  an  imperious 
necessity  for  the  higher  animals.  If  this  need  be  not 
satisfied  the  functional  activities  become  enervated  ; 
the  animal  falls  into  a  state  of  torpor ;  and  if  it  is 
capable  of  attenuated,  of  more  or  less  latent,  life  it 
sleeps  in  a  state  of  hibernation  ;  but  if  it  is  not 
capable  of  this,  it  dies.  The  warm-blooded  animal 
with  a  fixed  temperature  is  so  organized  that  this 
constancy  of  temperature  is  necessary  to  the  exercise 
and  to  the  conservation  of  life.  To  maintain  this 
indispensable  temperature  there  must  be  a  continual 
supply  of  thermal  energy.  According  to  this,  the 
necessity  of  alimentation  is  confused  with  the 
necessity  of  a  supply  of  heat  to  cover  the  deficit 
which  is  due  to  the  inevitable  cooling  of  the  organism. 
This  is  the  point  of  view  taken  up  by  theorists,  and 
we  cannot  say  that  they  have  no  right  to  do  so.  We 
can  only  protest  against  the  exaggeration  of  this 
principle,  and  the  subordination  of  the  other  roles  of 
food  to  this  single  role  as  a  thermogen.  It  is  the 
magnitude  of  the  thermal  losses  which,  according  to 
these  physiologists,  determines  the  need  for  food,  and 
regulates  the  total  value  of  the  maintenance  ration. 
From  the  quantitative  view  it  is  approximately  true. 
From  the  qualitative  point  of  view  it  is  false. 

Such  is  the  theory  opposed  to  the  theory  of 
chemical  and  vital  energy.  It  has  on  its  side  a  large 
number  of  experts,  among  whom  are  Rubner,  Stoh- 
mann,  and  von  Noorden.  It  has  been  defended  in  an 
article  in  the  Dictionnaire  de  Physiologic  by  Ch. 
Richet  and  Lapicque.  They  hold  that  thermogenesis 
absolutely  dominates  the  play  of  nutritive  exchanges  ; 


ALIMENTARY  ENERGETICS.  141 

and  it  is  the  need  for  the  production  of  beat  that 
regulates  the  total  demand  for  Calories  which  every 
organism  requires  from  its  ration.  It  is  not  became 
it  produces  too  much  heat  that  the  organism  gets  rid 
of  it  peripherally :  it  is  rather  because  it  inevitably 
disperses  it  that  it  is  adapted  to  produce  it. 

Rttbner's  Experiments, — This  conception  of  the  role 
of  alimentation  is  based  on  two  arguments.  The  first 
is  furnished  by  Rnbner's  last  experiment  (1893).  A 
dog  in  a  calorimeter  is  kept  alive  for  a  rather  long 
period  (two  to  twelve  days) ;  the  quantity  of  heat 
produced  in  this  lapse  of  time  is  measured,  and  it  is 
compared  with  the  heat  afforded  by  the  food.  In  all 
cases  the  agreement  is  remarkable.  But  is  it  possible 
that  there  should  be  no  such  agreement?  Clearly  no, 
because  there  is  a  well-known  regulating  mechanism 
which  always  exactly  proportions  the  kisses  and  the 
gains  of  heat  to  the  necessity  of  maintaining  the  fixed 
internal  temperature.  This  first  argument  is,  there- 
fore, not  conclusive. 

The  second  argument  is  drawn  from  what  has  been 
called  the  law  of  surfaces t  clearly  perceived  by  Reg- 
nault  and  Reiset  in  their  celebrated  memoir  in  1849, 
formulated  by  Rubner  in  1884.  and  beautifully 
demonstrated  by  Ch.  Richet.  In  comparing  the 
maintenance  rations  for  subjects  of  very  different 
weights,  placed  under  very  different  conditions,  it  is 
found  that  the  food  always  introduces  the  same  num- 
ber of  Calories  for  the  same  extent  of  skin — 1>,  for 
the  same  cooling  surface.  The  numerical  data 
collected  by  EL  Vbit  show  that,  under  identical  con- 
ditions, warm-blooded  animals  daily  expend  the  same 
quantity  of  heat  per  unit  of  surface — namely,  1.036 
Calories  per  square  yard.  The  average  ration  intro- 


142  LIFE    AND    DEATH. 

duces  exactly  the  amount  of  food  which  gives  off 
sensibly  this  number  of  Calories.  Now,  this  is  an 
interesting  fact,  but,  like  the  preceding,  it  has  no 
demonstrative  force. 

Objections.  The  Limits  of  Isodynamism. — On  the 
contrary,  there  are  serious  objections.  The  thermal 
value  of  the  nutritive  principles  only  represents  one 
feature  of  their  physiological  role.  In  fact,  animals 
and  man  are  capable  of  extracting  the  same  profit 
and  the  same  results  from  rations  in  which  one  of  the 
foods  is  replaced  by  an  isodynamic  proportion  of  the 
other  two — that  is  to  say,  a  proportion  developing  the 
same  quantity  of  heat.  But  this  substitution  has  very 
narrow  limits.  Isodynamism — that  is  to  say,  the 
faculty  that  food  has  of  supplying  pro  rata  its  thermal 
values — is  limited  all  round  by  exceptions.  In  the 
first  place,  there  are  a  few  nitrogenous  foods  that  no 
other  nutritive  principle  can  supply;  and  besides,  be- 
yond this  minimum,  when  the  supply  takes  place,  it  is 
not  perfect.  Lying  between  the  albuminoids  and  the 
carbohydrates  relatively  to  the  fats,  it  is  not  between 
these  two  categories  relatively  to  nitrogenous  sub- 
stances. If  the  thermal  power  of  food  were  the  only 
thing  that  had  to  be  considered  in  it,  the  isodynamic 
supply  would  not  fail  in  a  whole  category  of  principles 
such  as  alcohol,  glycerine,  and  the  fatty  acids.  Finally, 
if  the  thermal  power  of  a  food  is  the  sole  measure  of 
its  physiological  utility,  we  are  compelled  to  ask  why 
a  dose  of  food  may  not  be  replaced  by  a  dose  of  heat. 
External  warming  might  take  the  place  of  the  internal 
warming  given  by  food.  We  might  be  ambitious 
enough  to  substitute  for  rations  of  sugar  and  fat  an 
isodynamic  quantity  of  heat-giving  coal,  and  so 
nourish  the  man  by  suitably  warming  his  room.  In 


ALIMENTARY   ENERGETICS.  143 

reality,  food  has  many  other  offices  to  fulfil  than 
that  of  warming  the  body  and  of  giving  it  energy — 
that  is  to  say,  of  providing  for  the  functioual  activity 
of  the  living  machine.  It  must  also  serve  to  provide 
for  wear  and  tear.  The  organism  needs  a  suitable 
quantity  of  certain  fixed  principles,  organic  and 
mineral  These  substances  are  evidently  intended  to 
replace  those  which  have  been  involved  in  the  cycle 
of  matter,  and  to  reconstitute  the  organic  material. 
To  these  materials  we  may  give  the  name  of  histo- 
genetic  foods  (repairing  the  tissues),  or  of  plastic 
foods. 

§  5.  THE  PLASTIC  R6LE  OF  FOOD. 

Opinions  of  the  Early  Physiologists. — It  is  from  this 
point  of  view  that  the  ancients  regarded  the  role  of 
alimentation.  Hippocrates,  Aristotle,  and  Galen 
believed  in  the  existence  of  a  unique  nutritive  sub- 
stance, existing  in  all  the  infinitely  different  bodies 
that  man  and  the  animals  utilize  for  their  nourish- 
ment. It  was  Lavoisier  who  first  had  the  idea  of  a 
dynamogenic  or  thermal  role  of  foods.  Finally,  the 
general  view  of  these  two  species  of  attributes  and 
their  marked  distinction  is  due  to  J.  Liebig,  who 
called  them//<tt//V:  and  dynamogenic  foods.  In  addition 
he  thought  that  the  same  substance  should  accumulate 
the  same  attributes,  and  that  this  was  the  case  with 
the  albuminoid  foods,  which  were  at  once  plastic  and 
dynamogenic. 

Preponderance  of  Nitrogenous  Foods. — Magendie,  in 
1836,  was  the  pioneer  who  introduced  in  this  inter- 
minable list  of  foods  the  first  simple  division.  He 
divided  them  into  proteid  substances,  still  called 


144  LIFE   AND    DEATH. 

albuminoids,  nitrogenous,  quaternary,  and  ternary 
substances.  Proteid  substances  are  capable  of  main- 
taining life.  Hence  the  preponderant  importance 
given  by  the  eminent  physiologist  to  this  order  of 
foods.  These  results  have  since  been  verified.  Pfliager, 
of  Bonn,  gave  a  very  convincing  proof  of  this  a  few 
years  ago.  He  fed  a  dog,  made  it  work,  and  finally 
fattened  it,  by  giving  it  nothing  at  all  to  eat  but  meat 
from  which  had  been  extracted,  as  thoroughly  as 
possible,  every  other  substance.1  The  same  experiment 
showed  that  the  organism  can  manufacture  fats  and 
carbo-hydrates  at  the  expense  of  the  nitrogenous  food, 
when  it  does  not  find  them  ready  formed  in  the  ration. 
The  albumen  will  suffice  for  all  the  needs  of  energy  and 
and  matter.  To  sum  up,  there  is  no  necessary  fat,  no 
carbohydrate  is  necessary;  albuminoids  alone  are  in- 
dispensable. Theoretically,  the  animal  and  man  alike 
could  maintain  life  by  the  exclusive  use  of  proteid 
food;  but,  practically,  this  is  not  possible  for  man, 
because  of  the  enormous  amount  of  meat  which 
would  have  to  be  used  (3  kilogrammes  a  day). 

Ordinary  alimentation  comprises  a  mixture  of 
three  orders  of  substances,  and  to  this  mixture 
albumen  brings  the  plastic  element  materially  neces- 
sary for  the  reparation  of  the  organism  ;  it  also  is 
the  source  of  energy.  The  two  other  varieties  only 
bring  energy.  In  this  mixed  regimen  the  quantity 
of  albumen  must  never  descend  below  a  certain 
minimum.  The  efforts  of  physiologists  of  late  years 
have  tended  to  fix  with  precision  this  minimum 
ration  of  albuminoids — or  as  we  may  briefly  put  it, 

1  It  is  not  certain,  however,  that  all  the  precautions  taken 
have  the  desired  result.  You  cannot  entirely  deprive  meat  of  its 
carbohydrates. 


ALIMENTARY    ENERGETICS.  145 

of  albumen — below  which  the  organism  would  perish. 
Voit  had  found  118  grammes  of  albumen  necessary 
for  the  average  adult  man  weighing  70  kilos.  This 
figure  is  certainly  too  high.  The  Japanese  doctors, 
Mori,  TsuboT,  and  Murato,  have  shown  that  a  con- 
siderable portion  of  the  population  of  Japan  is 
content  with  a  diet  much  poorer  in  nitrogen,  and 
suffers  no  inconvenience.  The  Abyssinians,  according 
to  Lapicque,  ingest,  on  the  average,  only  67 
grammes  of  albumen  per  day.  A  Scandinavian  physi- 
ologist, Siven,  experimenting  on  himself,  found  that 
he  could  reduce  the  ration  of  albumen  necessary  to 
the  maintenance  and  equilibrium  of  the  organism  to 
the  lowest  figures  which  have  been  yet  reached — 
namely,  from  35  to  46  grammes  a  day.  These 
experiments,  however,  must  be  confirmed  and  inter- 
preted. Besides,  it  is  important  to  point  out  that  the 
most  advantageous  ration  of  albumen  requires  to  be 
a  good  deal  above  the  strictly  sufficient  quantity. 

It  only  remains  to  refer  to  several  other  recent 
researches.  The  most  important  of  many  are  those 
published  by  M.  Chauveau,  on  the  reciprocal  trans- 
formation of  the  immediate  principles  in  the  organism 
according  to  the  conditions  of  its  functioning  and 
the  circumstances  of  its  activity.  To  deal  with 
these  researches  with  as  much  detail  as  they  deserve, 
we  must  study  the  physiology  of  muscular  contraction 
and  of  movement — that  is  to  say,  of  muscular 
energetics. 


BOOK  III. 

THE   CHARACTERS  COMMON   TO   LIVING  BEINGS. 

Chapter  I.  Summary:  The  doctrine  of  vital  unity. — Chapter  II. 
The  morphological  unity  of  living  beings. — Chapter  III. 
The  chemical  unity  of  living  beings. — Chapter  IV.  The 
mutability  of  living  beings. — Chapter  V.  The  specific 
form,  its  acquisition,  and  reparation. — Chapter  VI.  Nutri- 
tion. 

CHAPTER  I. 

THE   DOCTRINE   OF  VITAL   UNITY. 

Phenomena  common  to  all  living  beings — Theory  of  vital 
duality — Unity  in  the  formation  of  immediate  principles — 
Unity  in  the  digestive  acts — The  common  vital  fund. 

WHEN  we  ask  the  various  philosophical  schools  what 
life  is,  some  show  us  a  chemical  retort,  and  others 
show  us  a  soul.  Whether  vitalists  or  of  the  mechanical 
school,  these  are  the  adversaries  who  since  philosophy 
began  have  vainly  contested  the  possession  of  the 
secret  of  life.  We  need  not  concern  ourselves  with  this 
eternal  quarrel.  We  need  not  ask  Pythagoras,  Plato, 
Aristotle,  Hippocrates,  Paracelsus,  Van  Helmont, 
and  Stahl  what  idea  they  formed  of  the  vital 
principle ;  nor  need  we  probe  to  the  depths  the 
ideas  of  living  nature  held  by  Epicurus,  Democritus, 
I46 


THE   DOCTRINE  OF  VITAL   UNITY.  147 

Boerhaave,  Willis,  and  Lamettrie ;  nor  need  we 
apply  to  the  iatrocnechanicians  nor  to  the  chemists. 
We  may  do  better  than  that.  We  may  ask  nature 
itself. 

Phenomena  Common  to  Living  Beings.  —  Nature 
shows  us  an  infinite  number  of  beings,  animal  or 
vegetable,  described  in  ordinary  language  as  Ihing 
beings.  This  language  implicitly  assumes  something 
common  to  them  all,  a  universal  manner  of  being 
which  belongs  to  them  without  distinction,  without 
regard  to  differences  of  species,  types,  or  kingdoms. 
On  the  other  hand,  anatomical  analysis  teaches  us 
that  animated  beings  and  plants  may  be  divided  into 
parts  ever  decreasing  in  complexity,  of  which  the 
last  and  the  simplest  is  the  anatomical  element,  the 
«#,  the  microscopic  organic  unit  which,  too,  is  alive- 
Common  opinion  suspects  that  all  these  beings, 
whether  entire  as  in  the  case  of  animal  and  vege- 
table individuals,  or  fragmentary  as  in  the  case  of 
cellular  elements,  have  the  same  manner  of  being, 
and  present  the  same  body  of  common  characteristics 
which  rightly  gives  them  this  unmistakable  title  of 
living  beings.  Life  then  essentially  would  be  this 
manner  of  being,  common  to  aninmls,  vegetables,  and 
their  elements.  To  seize  in  isolation  these  common, 
necessary,  and  permanent  features,  and  then  to 
synthetize  them  into  a  whole,  will  be  the  really 
scientific  method  of  defining;  life,  and  of  explaining 
its  nature. 

And  here  then  immediately  arises  a  fundamental 
question  which  gives  one  pause,  a  question  of  fact 
which  must  be  solved  before  we  can  go  further. 
Is  there  really  a  common  manner  of  being  in  all 
these  tilings  ?  Are  animal  life,  vegetable  life,  and  the 


148  LIFE  AND   DEATH. 

life  of  the  elements  or  elementary  life,  all  the  same? 
Is  there  a  sum  total  of  characteristics  which  may 
define  life  in  general  ? 

The  physiologists,  following  in  the  steps  of  Claude 
Bernard,  respond  in  the  affirmative.  They  accept  as 
valid  and  convincing  the  proof  given  of  this  vital 
community  by  the  illustrious  experimentalist.  How- 
ever, there  are  some  rare  exceptions  to  this  universal 
assent.  In  this  concert  of  approval  thsre  is  at  least 
one  discordant  voice,  that  of  M.  F.  Le  Dantec.1 

1  M.  Le  Dantec,  of  whose  philosophical  and  rigorously 
systematic  mind  I  have  the  highest  opinion,  has  laid  down  a 
new  conception  of  life,  the  essential  basis  of  which  is  this  very 
distinction  between  elementary  life  and  ordinary  life;  between 
the  life  of  the  elements  or  of  the  beings  formed  from  a  single 
cell,  protophytes  and  protozoa,  and  the  life  of  ordinary  animals 
and  plants,  which  are  multicellular  complexes,  and  for  that 
reason  called  metazoa  and  metaphytes. 

Further,  in  the  elementary  life  peculiar  to  monocellular 
beings  (protozoa  and  cellular  elements),  M.  Le  Dantec  dis- 
tinguishes three  manners  of  being:— The  first  condition,  which 
is  elementary  life  manifested  in  all  its  perfection,  cellular 
health ;  the  second  condition  is  deteriorated  elementary  life, 
cellular  disease;  and  the  third  condition,  which  is  latent  life. 
I  should  say  at  once  that  in  so  far  as  the  fundamental  dis- 
tinction of  the  phenomena  of  elementary  life  and  those  of  the 
general  life  of  animals  and  ordinary  plants,  metazoa  or  meta- 
phytes, is  concerned,  we  find  it  neither  justified  nor  useful. 
And  further,  manifested  elementary  life,  as  M.  Le  Dantec 
understands  it,  would  only  belong  to  a  small  number  of 
elementary  Sitings—tot  the  protozoa,  starting  with  the  infusoria, 
are  not  among  the  number — and  to  a  still  smaller  number  of 
anatomical  elements,  since  among  the  vertebrates  we  recognize 
as  almost  the  only  elements  satisfying  it,  the  ovule,  and  perhaps 
the  leucocyte.  Physiologists,  therefore,  do  not  agree  with 
M.  Le  Dantec  as  to  the  utility  of  adding  one  condition  more  to 
those  we  all  admit— namely,  manifested  animal  life  and  latent 
life. 


THE    DOCTRINE   OF   VITAL    UNITY.  149 

The  Doctrine  of  the  Vital  Duality  of  Animals  and 
Plants. — There  are,  therefore,  biologists  who,  in  the 
domain  of  theory  and  in  virtue  of  more  or  less  well- 
founded  conceptions  or  interpretations,  separate 
elementary  life  from  other  vital  forms,  and  thus  break 
the  bond  of  vital  unity  proclaimed  by  Claude  Bernard. 
This  monistic  doctrine  at  the  outset  met  with  other 
opponents,  and  that,  too,  in  the  domain  of  facts. 
But  it  triumphed  over  them  and  became  established. 
We  have  to  deal  with  scientists  like  J.  B.  Dumas  and 
Boussingault,  who  drew  a  dividing  line  between 
animal  life  and  vegetable  life. 

But  let  us  in  a  few  words  recall  to  the  reader  this 
victorious  struggle  of  the  monistic  doctrine  against 
the  dualism  of  the  two  kingdoms.  If  we  consider  an 
animal  in  action,  said  the  champions  of  vital  dualism, 
we  agree  that  it  feels,  moves,  breathes,  digests,  and 
finally,  that  it  destroys  by  a  real  operation  of  chemical 
analysis  the  materials  afforded  to  it  by  its  ambient 
world.  It  is  in  these  phenomena  that  are  manifested 
its  activity,  its  life.  Now,  added  the  dualists,  plants 
do  not  feel,  do  not  move,  do  not  breathe,  and  do  not 
digest.  They  build  up  from  immediate  principles, 
by  an  operation  of  chemical  synthesis,  the  materials 
they  borrow  from  the  soil  which  bears  them,  or  from 
the  atmosphere  which  surrounds  them.  There  is, 
therefore,  nothing  in  common  between  the  repre- 
sentatives of  the  two  kingdoms  if  we  confine  ourselves 
to  the  examination  of  the  actual  phenomena  which 
take  place  in  them.  To  find  a  resemblance  between 
the  animal  and  the  vegetable,  said  the  dualists,  we 
must  set  aside  what  they  do,  for  they  do  different,  or 
even  contrary  things.  We  must  consider  whence 
they  come  and  what  they  become.  Both  originate 


150  LIFE   AND   DEATH. 

in  organisms  similar  to  themselves.  They  grow, 
evolve,  and  generate  as  they  themselves  weie 
generated.  In  other  words,  while  their  acts  separate 
plants  from  animals,  their  mode  of  origin  and 
evolution  alone  bring  them  together.  Such  analogies 
are  of  no  slight  importance ;  but  they  were  neutralized 
by  their  dissimilarities,  which  were  exaggerated  by 
fthe  dualistic  school. 

It  is  clear  that  the  word  life  would  lose  all  actual 
significance  to  those  who  would  reduce  it  to  the 
faculty  of  evolution,  and  who  would  separate  all  its 
real  manifestations  in  animated  beings  and  in  plants. 
If  there  are  two  lives,  the  one  animal  and  the  other 
vegetable,  there  are  no  more ;  or,  what  comes  to  the 
same  thing,  there  is  an  infinite  number  of  lives  which 
have  nothing  in  common  but  the  name,  or  at  most, 
the  possession  of  some  secondary  characteristics. 
There  are  as  many  of  them  as  there  are  different 
beings,  for  each  has  its  own  particular  evolution. 
Here  the  specific  is  the  negation  of  the  general  and 
it  destroys  it  instead  of  being  subordinate  to  it.  The 
principle  of  life  becomes  for  each  being  something  as 
individual  as  its  own  evolution.  And  this,  if  we 
think  it  out,  is  how  the  philosophers  look  at  life,  and 
it  is  the  real  reason  of  their  disagreement  with  the 
physiological  school. 

-  Proof  of  the  Monistic  TJieory, — On  the  other  hand, 
under  the  disguise  of  living  forms,  the  physiologist 
recognizes  the  existence  of  an  identical  basis.  His 
trained  ear  marks  amid  the  overcharged  in- 
strumentation of  the  vital  work  the  recognizable 
undertones  of  a  constant  theme.  It  was  the  work  of 
Claude  Bernard  to  bring  this  common  basis  to 
light.  He  shows  that  plants  live  as  animals  do, 


THE   DOCTRINE   OF  VITAL   UNITY.  151 

that  they  breathe,  digest,  have  sensory  reactions, 
move  essentially  like  animals,  destroy  and  build  up 
in  the  same  manner  the  immediate  chemical  prin- 
ciples. For  that  purpose  it  was  necessary  to  pass  in 
review,  examining  them  from  their  foundation  and 
distinguishing  the  essential  from  the  secondary,  the 
different  vital  manifestations — digestion,  respiration, 
sensibility,  motility,  and  nutrition.  This  is  what 
Claude  Bernard  did  in  his  work  Sur  les  Phenomenes 
de  la  vie  communs  attx  animaux  et  aux  plantes.  We 
need  only  to  sketch  in  broad  outline  the  character- 
istic features  of  his  lengthy  demonstration. 

Unity  in  tJte  Formation  of  Immediate  Chemical 
Principles. — The  first  and  most  important  of  the 
differences  pointed  out  between  the  life  of  animals 
and  that  of  plants  was  relative  to  the  formation  of 
immediate  principles.  On  this  ground,  indeed,  vital 
dualism  raised  its  fortress.  The  animal  kingdom 
was  considered  in  its  totality  as  the  parasite  of  the 
vegetable  kingdom.  To  J.  B.  Dumas,  animals, 
whatever  they  may  be,  make  neither  fat  nor  any 
elementary  organic  matter ;  they  borrow  all  their 
foods,  whether  they  be  sugars  or  starches,  fats  or 
nitrogenous  substances,  from  the  vegetable  kingdom. 
About  the  year  1843  the  researches  of  the  chemists, 
and  of  Payen  in  particular,  succeeded  in  proving  the 
presence,  almost  constant,  of  fatty  matters  in  vege- 
tables ;  and,  further,  these  matters  existed  there  in 
proportions  more  than  sufficient  to  explain  how 
the  beast  which  fed  upon  them  was  fattened.  The 
chemists  attributed  to  nature  as  much  practical  sense 
as  they  themselves  possessed ;  and  since  the  hay  and 
the  grass  of  the  ration  brought  fat  ready  made  to  the 
horse,  the  cow,  and  the  sheep,  they  declared  that  the 

ii 


152  LIFE    AND    DEATH. 

animal  organism  had  nothing  whatever  to  do  but  to 
put  this  food  into  the  tissues,  or  to  arrange  for  it  to 
pass  into  the  milk.  But  nature  is  not  so  wise  and 
economical  as  was  supposed  at  the  Academic  des 
Sciences.  After  a  memorable  debate,  in  which 
Dumas,  Boussingault,  Payen,  Liebig,  Persoz,  Chossat, 
Milne-Edwards,  and  Flourens  took  part,  and,  later  on, 
Berthelot  and  Claude  Bernard,  it  was  agreed  that 
the  animal  does  not  grow  fat  from  the  fatty  food 
which  is  supplied  it,  and  that  it  makes  its  own  fat 
just  as  the  vegetable  does,  but  in  another  manner. 
In  the  same  way  sugar,  the  normal  constituent  sub- 
stance necessary  for  the  nutrition  of  animals  and 
plants,  instead  of  being  a  vegetable  product  passing 
by  alimentation  from  the  herbivorous  animals  and 
thence  to  the  carnivorous,  is  manufactured  by  the 
animal  itself.  Generally  speaking,  immediate  prin- 
ciples have  an  equal  claim  to  existence  in  the  two 
kingdoms.  Both  form  and  destroy  the  substances 
indispensable  to  life. 

Here,  then,  one  of  the  barriers  between  animal  life 
and  vegetable  life  is  overthrown  and  destroyed. 

Unity  of  Digestive  Acts  in  Animals  and  Plants. — 
Similarly,  another  barrier  falls  if  we  show  that 
digestion,  long  considered  the  exclusive  function  of 
animals,  and,  in  particular,  of  the  higher  animals,  is 
in  reality  universal. 

Cuvier  pointed  out  the  absence  of  a  digestive 
apparatus  as  a  very  general  and  distinctive  char- 
acteristic of  plants.  But  the  absence  of  a  digestive 
apparatus  does  not  necessarily  imply  the  absence  of 
digestion.  The  essential  act  of  digestion  is  indepen- 
dent of  the  infinite  variety  of  the  organs,  just  as  a 
reaction  is  independent  of  the  form  of  the  vessel  in 


THE    DOCTRINE    OF   VITAL    UNITY.  153 

which  it  takes  place.  It  is,  in  fact,  a  chemical 
transformation  of  an  alimentary  substance.  This 
transformation  may  be  realized  outside  the  organism, 
in  ^'itr0,  just  as  it  can  in  the  living  being  without 
masticating  organs,  without  an  intestinal  apparatus, 
without  glands,  in  a  vessel  placed  in  a  stove,  simply 
by  means  of  a  few  soluble  ferments — pepsine,  trypsine, 
amylolytic  diastases. 

All  alimentary-  substances,  whether  taken  from 
without  or  borrowed  from  the  reserves  accumulated 
in  the  internal  stores  of  the  organism,  must  undergo 
preparation.  This  preparation  is  digestion.  Diges- 
tion is  the  prologue  of  nutrition.  It  is  over  when  the 
reparative  substance,  whether  food  or  reserve-stuff, 
is  brought  into  a  state  enabling  it  to  pass  into  the 
blood,  and  to  be  utilized  by  the  organism. 

The  Identity  of  Categories  of  Foods  in  the  Two 
Kingdoms. — Now  the  alimentary  substances  are  the 
same  in  the  two  kingdoms,  and  so  is  their  digestive 
preparation.  Alimentary  materials  are  of  four 
kinds :  albuminoid,  starchy,  fatty,  and  sugary  sub- 
stances. The  animal  takes  them  from  without 
(food  properly  so-called),  or  from  within  freserve- 
stufF).  Man  obtains  starch,  for  instance,  from  different 
farinaceous  dishes.  It  may,  however,  equally  well 
be  borrowed  from  the  reserve  of  flour  that  we  cam- 
within  us  in  our  liver,  which  is  a  veritable  granary, 
full  of  floury  substance,  glycogen.  And  so  it  is  with 
vegetables.  The  potato  has  its  store  of  flour  in  its 
tuber  just  as  the  animal  has  in  its  liver.  The  grain 
which  is  about  to  germinate  has  it  in  reserve-stuff  in 
its  cotyledons,  or  in  its  albumen.  The  bud  which  is 
about  to  develop  into  a  tree  or  a  flower  carries  it  at 
its  base 


154  LIFE   AND   DEATH. 

The  same  conclusions  are  true  for  another  class 
of  substances,  the  sugars.  They  may  be  a  food  taken 
from  without,  or  a  reserve  deposited  in  the  tissues. 
The  animal  takes  from  without,  in  fruits  for  instance, 
the  ordinary  sugar  which  pleases  its  taste.  Beetroot, 
when  flowering  and  fructifying,  draws  this  substance 
from  its  roots  in  which  stores  have  been  amassed. 
The  sugar  cane  when  running  to  seed  takes  the 
sugar  from  the  stores  which  it  possesses  in  its  cane. 
Brewer's  yeast,  the  sacckaromyces  cerevisits,  the  agent 
of  alcoholic  fermentation,  finds  this  same  substance  in 
the  sugary  juices  favourable  to  its  development. 

In  the  same  way,  identically  fatty  substances, 
either  in  the  form  of  food  or  of  reserve-stuff,  serve 
for  nutrition  to  animals  and  vegetables ;  and  that  is 
again  true  of  the  substances  of  the  fourth  class, 
albuminoids,  identical  in  the  two  kingdoms,  foods  or 
reserve-stuff,  equally  utilizable  in  both  after  digestion. 

Identity  of  the  Digestive  Agents  and  Mechanisms  in 
Plants  and  Animals. — Now,  the  results  of  contem- 
porary research  have  been  to  establish  a  surprising 
resemblance  in  the  modifications  experienced  by  these 
foods,  or  reserve  stuffs,  in  animals  and  plants;  and 
even  resemblances  in  the  agents  which  realize  them, 
and  in  the  mechanisms  by  which  they  are  performed. 
There  is  a  real  unity.  The  flour  accumulated  in  the 
tuber  of  the  potato  is  liquefied  and  digested  on  the 
appearance  of  the  buds  or  of  the  flower,  just  as  the 
starch  of  the  liver  or  the  alimentary  flour  is  digested 
by  the  animal.  The  fatty  matter  which  is  stored  up 
in  the  oleaginous  grain  is  digested  at  the  moment  of 
germination,  just  as  the  fat  during  a  meal  is  digested 
in  the  animal's  intestine.  As  the  beetroot  begins  to 
run  to  seed,  the  root  gives  up  part  of  its  store  of 


THE    DOCTRINE    OF   VITAL    UNITY.  155 

sugar,  and  this  reserve  stuff  is  distributed  throughout 
the  stalk  after  having  been  digested,  exactly  as  would 
have  been  the  case  in  the  digestive  canal  of  man. 

Vegetables,  then,  really  digest.  The  four  classes  of 
substances  mentioned  above  are  really  digested  in 
order  to  pass  from  their  actual  form,  a  form  unsuitable 
for  interstitial  exchanges,  to  another  form  suitable  for 
nutrition.  As  there  are  four  kinds  of  foods,  so  there 
are  four  kinds  of  digestions,  four  kinds  of  ferment- 
producing  agents — amylolytic,1  proteolytic,2  sacchar- 
ine, and  lipasic3  diastases,  identical  in  the  animal 
and  the  plant  Identity  of  ferments  implies  identity 
of  digestions.  Going  down  to  the  very  basis  of 
things,  the  digestive  act  is  nothing  but  the  action  of 
this  ferment  This  is  the  crux  of  the  whole  question. 
All  else  is  only  difference  in  scene,  varying  in  the 
means  of  execution  and  in  the  accessories.  The 
difference  arises  from  the  stage  on  which  it  takes 
place,  but  the  piece  which  is  being  played  is  the 
same,  and  the  actors  are  the  same,  and  so  is  the 
action  of  the  play. 

"~  This  identity  between  animal  and  vegetable  life  is 
found  in  the  phenomena  of  respiration  and  of  motility. 
The  limits  of  this  book  do  not  allow  of  our  entering 
into  the  details  of  facts.  Besides,  the  facts  are  well 
known,  and  may  be  found  in  any  treatise  on  general 
physiology.  This  science,  therefore,  enables  us  to 
perceive  the  impn^jng  unity  of  life  in  its  essential 
manifestations. 

1  Amylolytic  ferments  change  starch  and  glycogen  (atnyloses) 
into  sugar. — TR. 

2  Proteolytic   ferments   change   proteids   into   peptones  and 
proteoses. — TR. 

3  The  enzyme  known  as  lipase  splits  the  fat  or  oil  in  germ- 
inating seeds  into  a  fatty  acid  and  glycerine. — TR. 


I5&  LIFE   AND    DEATH. 

The  community  of  the  phenomena  of  vitality  in 
animals  and  plants  being  thus  placed  beyond  a  doubt, 
we  must  now  discover  the  reason  why.  This  reason 
is  to  be  found  in  their  anatomical  and  in  their 
chemical  unity.  The  fundamental  phenomena  are 
common  because  the  composition  is  common,  and 
because  the  universal  anatomical  basis,  the  cell, 
possesses  in  all  cases  a  sum  total  of  identical 
properties. 

If  we  appeal  to  physiology  for  the  characteristics 
common  to  living  beings,  it  will  generally  give  us  the 
following: — A  structure  or  organization;  a  certain 
chemical  composition  which  is  that  of  living  matter ; 
a  specific  form ;  an  evolution  which  in  the  earliest 
stage  occasions  the  being  to  grow  and  develop  until 
it  is  divided,  and  which  in  the  highest  stage  includes 
one  or  more  evolutive  cycles  with  growth,  the  adult 
stage,  senility,  and  death ;  a  property  of  increase  or 
nutrition,  with  its  consequence — namely,  a  relation  of 
material  exchanges  with  the  ambient  medium ; — and 
finally,  a  property  of  reproduction.  It  is  important 
to  pass  them  rapidly  in  review. 


CHAPTER   II. 

MORPHOLOGICAL  UNITY  OF   LIVING   BEINGS. 

§  i.  The  cellular  theory.  First  period:  division  of  the  organism 
— >?  2.  Second  period:  division  of  the  cell — Cytoplasm — 
The  nucleus — §  3.  Physical  constitution  of  living  matter — 
The  micellar  theory — §  4.  Individuality  of  complex  beings 
— The  law  of  the  constitution  of  organisms. 

THE  first  characteristic  of  the  living  beings  is 
organization.  By  that  we  mean  that  they  have  a 
structure;  that  they  are  complex  bodies  formed  of 
smaller  aliquot  parts  and  grouped  according  to  a 
certain  disposition.  The  most  simple  elementary 
being  is  not  yet  homogeneous.  It  is  heterogeneous. 
It  is  organized.  The  least  complex  protoplasms, 
that  of  bacteria,  for  example,  still  possess  a 
physical  structure;  Kunstler  distinguishes  in  them 
two  non-miscible  substances,  presenting  an  alveolar 
organization.  Thus  animals  and  plants  present  an 
organization,  and  it  is  sensibly  constant  from  one  end 
to  the  other  of  the  scale  of  beings.  There  is  a 
morphological  unity. 

§  i.  THE  CELLULAR  THEORY.    FIRST  PERIOD: 
DIVISION  OF  THE  ORGANISM  INTO  CELLS. 

Cellular     T/ieory.      First    Period. — Morphological 
unity    results    from    the    existence    of   a    universal 
ID? 


'15$  'LIFE    AND    DEATH. 

anatomical  basis,  the  cell.  The  cellular  theory  sums 
up  the  teaching  of  general  anatomy  or  histology. 

At  the  beginning  of  the  nineteenth  century  anatomy 
was  following  a  routine  dating  from  ancient  times. 
It  divided  animal  and  vegetable  machines  into  units 
in  descending  order,  first  into  different  forms  of 
apparatus  (circulatory,  respiratory,  digestive,  etc.); 
then  the  apparatus  into  organs  examined  one  by  one, 
figuring  and  describing  each  of  them  from  every 
point  of  view  with  scrupulous  accuracy  and  untiring 
patience.  If  we  think  of  the  duration  of  these 
researches — the  Iliad,  as  Malgaigne  says,  already 
containing  the  elements  of  a  very  fine  regional 
anatomy — and  especially  of  the  powerful  impulse 
they  received  in  the  seventeenth  and  eighteenth 
centuries,  we  shall  understand  the  illusion  of  those 
who,  in  the  days  of  X.  Bichat,  could  fancy  that  the 
task  of  anatomy  was  almost  ended. 

As  a  matter  of  fact  this  task  was  barely  begun,  for 
nothing  was  known  of  the  intimate  structure  of  the 
organs.  X.  Bichat  accomplished  a  revolution  when 
he  decomposed  the  living  body  into  tissues.  His 
successors,  advancing  a  step  in  the  analysis,  dis- 
sociated the  tissues  into  elements.  These  elements, 
which  one  would  have  thought  were  infinitely  varied, 
were  reduced  in  their  turn  to  one  common  prototype, 
the  cell. 

The  living  body,  disaggregated  by  the  histologist, 
resolves  under  the  microscope  into  a  dust,  every  grain 
of  which  is  a  cell.  A  cell  is  an  anatomical  element 
the  constitution  of  which  is  the  same  from  one  part 
to  the  other  of  the  same  being,  and  from  one  being  to 
another;  and  its  dimensions,  which  are  sensibly 
constant  throughout  the  whole  of  the  living  world, 


MORPHOLOGICAL    UNITY   OF    LIVING    BEINGS.     159 

have  an  average  diameter  of  several  thousandths  of 
a  millimetre — />.,  of  several  microns.  This  element, 
the  cell,  is  a  real  organ.  It  is  smaller,  no  doubt,  than 
those  described  by  the  ancient  anatomists,  but  it  is  not 
less  complex.  Its  complexity  is  only  revealed  later. 
It  is  an  organic  unit.  Its  form  varies  from  one 
element  to  another.  Its  substance  is  a  semi-fluid 
mass,  a  mixture  of  different  albuminoids.  In  the 
mean  value  of  its  dimensions,  so  carefully  measured — 
exceptis  excipiendis — we  have  a  condition  the  signi- 
ficance of  which  has  not  yet  been  discovered,  but 
which  may  be  of  great  value  in  the  explanation  of  its 
peculiar  activities. 

Such  is  the  result  to  which  have  converged  the  re- 
searches of  the  biologists  who  have  examined  plants 
or  the  lower  animals,  as  well  as  of  the  anatomists  who 
have  been  more  especially  occupied  with  the  verte- 
brates and  with  man.  All  their  researches  have 
brought  them  to  the  same  conclusion — the  cellular 
theory.  Either  living  beings  are  composed  of  a  single 
cell — as  is  the  case  with  the  microscopic  animals  called 
protozoa,  and  the  microscopic  vegetables  called  proto- 
phytes — or,  they  are  cellular  complexes,  metasoa  or 
nutaphytes — that  is  to  say,  associations  of  these 
microscopic  organic  units  which  are  called  cells. 

The  Law  of  tJie  Composition  of  Organisms. — The 
law  of  the  composition  of  organisms  was  discovered 
in  1838  by  Schleiden  and  Schwann.  From  that  time 
up  to  1875  it  niay  be  said  that  micrographers  have 
spent  their  time  in  examining  every  organ  and  every 
tissue,  muscular,  glandular,  conjunctive,  nervous,  etc., 
and  in  showing  that  in  spite  of  their  varieties  of 
aspect  and  form,  of  the  complexity  of  structures  due 
to  cohesion  and  fusion,  they  all  resolve  into  the  com- 


l6o  LIFE    AND    DEATH. 

mon  element,  the  cell.  Contemporary  anatomists, 
Koelliker,  Max  Schultze,  and  Ranvier,  have  thus 
established  the  generality  of  the  cellular  constitution, 
while  zoologists  and  botanists  confirm  the  same  law 
for  all  animals  and  vegetables,  and  exhibit  them  all 
as  either  unicellular  or  multicellular. 

The  Cellular  Origin  of  Complex  Beings. — At  the 
same  time  embryogenic  researches  showed  that  all 
beings  spring  from  a  corpuscle  of  the  same  type. 
Going  back  in  the  history  of  their  development  to  the 
most  remote  period,  we  find  a  cell  of  very  constant 
constitution — namely,  the  ovule.  This  truth  may  be 
expressed  by  changing  a  word  in  Harvey's  celebrated 
aphorism — omne  vivum  ex  ovo ;  we  now  say  omne 
vivum  e  cellula.  The  myriads  of  differentiated  ana- 
tomical elements  whose  association  forms  complex 
beings  are  the  posterity  of  a  cell,  of  the  primordial 
ovule,  unless  they  are  the  posterity  of  another  equiva- 
lent cell.  The  second  task  of  histology  in  the  latter 
half  of  the  nineteenth  century  consisted  in  following 
up  the  filiation  of  each  anatomical  element  from  the 
cell-egg  to  its  state  of  complete  development. 

The  whole  cellular  theory  is  contained  in  the 
two  following  statements,  which  establish  the  mor- 
Dhological  unity  of  living  beings: — Everything  is  a 
?ell,  everything'  comes  from  an  initial  cell;  the  cell 
aeing  defined  as  a  mass  of  substance,  protoplasm  or 
protoplasms,  of  an  average  diameter  of  a  few  microns. 

•  §  2.  THE  SECOND  PERIOD  :  THE  DIVISION  OF 
THE  CELL. 

Second  Period :  Constitution  of  the  £>//.— This  was, 
however,  only  the  first  phase  in  the  analytical  study 


MORPHOLOGICAL    UNITY   OF   LIVING    BEINGS.     l6l 

of  the  living  being.  A  second  period  began  in 
1873  with  the  researches  of  Strassburger,  Biitschli, 
Flemming,  Kuppfer,  Fromann,  Heitzmann,  Balbiani, 
Guignard,  Kunstler,  etc.  These  observers  in  their 
turn  submitted  this  anatomical,  this  infinitely  small 
cellular  microcosm,  to  the  same  penetrating  dissection 
their  predecessors  had  applied  to  the  whole  organ- 
ism. They  brought  us  down  one  degree  lower  into 
the  abyss  of  the  infinitely  small.  And  as  Pascal, 
losing  himself  in  these  wonders  of  the  imperceptible, 
w  in  the  body  of  the  mite  which  is  only  a  point, 
"  parts  incomparably  smaller,  legs  with  joints,  veins  in 
the  legs,  blood  in  the  veins,  humours  in  the  blood, 
drops  in  the  humours,  vapours  in  these  drops,"  so 
contemporary  biologists  have  shown  in  the  epitome 
of  organism  called  a  cell,  an  edifice  which  itself  is 
marvellously  complex. 

Tlie  Cytoplasm. — The  observers  named  above  re- 
vealed to  us  the  extreme  complexity  of  this  organic 
unit  Their  researches  have  shown  us  the  structure 
of  the  two  parts  of  which  it  is  composed — the  cellular 
protoplasm  and  the  nucleus.  They  have  determined 
the  part  played  by  each  in  genetic  multiplication. 
They  have  shown  that  the  protoplasm  which  forms  the 
body  of  the  cell  is  not  homogeneous,  as  was  at  first 
supposed.  The  idea  which  was  mooted  later,  that 
this  protoplasm  was  formed,  to  use  Sachs'  words,  of  a 
kind  of  "  protoplasmic  mud," — i.e.,  of  a  dust  consisting 
of  grains  and  granules  connected  by  a  liquid, — is  no 
longer  accurate.  There  is  a  much  simpler  view  of  the 
case.  According  to  Leydig  and  his  pupils,  we  must 
compare  the  protoplasm  to  a  sponge  in  the  meshes  of 
which  is  lodged  a  fluid,  transparent,  hyaline  substance, 
a  kind  of  cellular  juice,  hyaloplasm.  From  the 


l62  LIFE   AND   DEATH. 

chemical  point  of  view  this  cellular  juice  is  a  mixture 
of  very  different  materials,  albumens,  globulins,  carbo- 
hydrates, and  fats,  elaborated  by  the  cell  itself.  It  is 
a  product  of  vital  activity ;  it  is  not  yet  the  seat  of 
this  activity.  The  living  matter  has  taken  refuge  in 
the  spongy  tissue  itself,  in  the  spongioplasm. 

According  to  other  histologists,  the  comparison  of 
protoplasm  to  a  spongy  mass  does  not  give  the 
most  exact  idea,  and,  in  particular,  it  does  not  furnish 
the  most  general  idea.  It  would  be  far  better  to  say 
that  the  protoplasm  possesses  the  structure  of  foam 
or  lather.  As  was  seen  by  Kunstler  in  1880,  a  com- 
parison with  some  familiar  objects  gives  the  best  idea. 
Nothing  could  be  more  like  protoplasm  physically 
than  the  culinary  preparation  known  as  sauce  mayon- 
naise^ made  with  the  aid  of  oil  and  a  liquid  with 
which  oil  does  not  mix.  Emulsions  of  this  kind  were 
made  artificially  by  Butschli.  He  noted  that  these 
preparations  mimicked  all  the  aspects  of  cellular 
protoplasm.  Thus,  in  the  living  cell  there  is  a 
mixture  of  two  liquids,  non-miscible  and  of  unequal 
fluidity.  This  mixture  gives  rise  to  the  formation  of 
little  cells.  The  more  consistent  substance  forms 
their  supporting  framework  (Leydig's  spongioplasm), 
while  the  other,  which  is  more  fluid,  fills  its  interior 
(hyaloplasm). 

However  that  may  be,  whether  the  primitive 
organization  of  the  cellular  protoplasm  be  that  of  a 
sponge,  as  is  asserted  by  Leydig,  or  that  of  a  sauce 
mayonnaise^  as  is  claimed  by  Butschli  and  Kunstler, 
the  complexity  does  not  rest  there.  Further  recourse 
must  be  made  to  analysis.  Just  as  the  tissue  of  a 
sponge,  when  torn,  shows  the  fibres  which  constitute 
it,  so  the  spongioplasm,  the  parietal  substance,  is 


MORPHOLOGICAL    UNITY   OF   LIVING    BEINGS.     163 

exhibited  as  formed  of  a  tangle  of  fibrils,  or  better 
still,  of  filaments  or  ribbons  (in  Greek,  mitome\  which 
are  called  chromatic  filament* •,  because  they  are  deeply 
stained  when  the  cell  is  plunged  into  aniline  dye.  In 
each  of  these  filaments,  the  substance  of  which  is 
called  chromatin,  the  devices  of  microscopic  examina- 
tion enable  us  to  discover  a  series  of  granulations  like 
beads  on  a  string,  the  microsonus  or  bioblasts,  con- 
nected one  with  the  other  by  a  sort  of  cement, 
Schwartz's  linin,  which  is  a  kind  of  nuclein. 

And  let  us  add,  to  complete  this  summary  of  the 
constitution  of  cellular  protoplasm,  that  it  presents,  at 
any  rate  at  a  certain  moment,  a  remarkable  organ, 
the  centrosome,  which  plays  an  important  part  in 
cellular  division.  Its  pre-existence  is  not  certain. 
Some  writers  make  it  issue  from  the  nucleus.  At  the 
moment  of  cellular  division  it  appears  like  a  com- 
pressed mass  of  granulations,  which  may  be  deeply 
stained.  Around  it  is  seen  a  clear  unstainable  zone, 
called  the  attraction-sphere ;  and  finally,  beyond  this 
is  a  crown  of  striae,  which  diverge  like  the  rays  of  a 
halo — />.,  the  aster.  In  conclusion,  there  are  yet  in 
the  cellular  body  three  kinds  of  non-essential  bodies : 
the  vacuoles,  the  leucites,  and  various  inclusions.  The 
vacuoles  are  cavities,  some  inert,  some  contractile ;  the 
leucites  are  organs  for  the  manufacture  of  particular 
substances ;  the  inclusions  are  the  manufactured  pro- 
ducts, or  wastes. 

TJie  Nucleus.  —  Every  cell  capable  of  living, 
growing,  and  multiplying,  possesses  a  nucleus  of 
constitution  very  analogous  to  the  cellular  mass 
which  surrounds  it  The  anatomical  elements  in 
which  no  nucleus  is  found,  such  as  the  red  globules 
of  blood  in  adult  mammals,  are  bodies  which  are 


164  LIFE   AND   DEATH. 

certain,  sooner  or  later,  to  disappear.  There  is  there- 
fore no  real  cell  without  a  nucleus,  any  more  than 
there  is  a  nucleus  without  a  cell.  The  exceptions  to 
this  law  are  only  apparent.  Histologists  have 
examined  them  one  by'  one,  and  have  shown  their 
purely  specious  character.  We  may  therefore  lay 
aside,  subject  to  possible  appeal  from  this  decision, 
organisms  such  as  Haeckel's  monera  and  the  problem 
of  finding  out  if  bacteria  really  have  a  nucleus.  The 
very  great,  if  not  the  absolute  generality  of  the 
nuclear  body,  must  be  admitted. 

It  hence  follows  that  there  is  a  nuclear  protoplasm 
and  a  nuclear  juice,  just  as  we  have  seen  that  there  is  a 
protoplasm  and  a  cellular  juice.  What  was  just  said  of 
the  one  may  now  be  repeated  of  the  other,  and  perhaps 
with  even  more  emphasis.  The  nuclear  protoplasm 
is  a  filamentary  mass  sometimes  formed  of  a  single 
mitome  or  cord,  folded  over  on  itself  and  capable  of 
being  unrolled.  The  mitome  in  its  turn  is  a  string 
of  microsomes  united  by  the  cement  of  the  linin. 
These  are  the  same  constituent  elements  as  before, 
and  the  language  of  science  distinguishes  them  one 
from  the  other  by  a  prefix  to  their  name  of  the  words 
cyto  or  karyo,  which  in  Greek  signify  cell  and  nucleus, 
according  as  they  belong  to  one  or  the  other  of  these 
organs.  These  are  mere  matters  of  nomenclature, 
but  we  know  that  in  the  descriptive  sciences  such 
matters  are  not  of  minor  importance. 

We  have  just  indicated  that  in  a  state  of  repose, — 
that  is  to  say,  under  ordinary  conditions, — the  structure 
of  a  nucleus  reproduces  clearly  the  structure  of  the 
cellular  protoplasm  which  surrounds  it.  The  nuclear 
essence  is  best  separated  from  the  spongioplasm. 
It  takes  more  clearly  the  form  of  a  filamentary 


MORPHOLOGICAL   UXTTT  OF  LIVING   BEDCGS.     165 

thread,  and  die  filaments  diemselves  (mitome)  show 
very  duck  chromatic  granulations,  or  midosomes, 
connected  by  die  linin. 

At  die  moment  of  reproduction  of  die  cell  these 
granulations  blend  into  a  stainable  «Jiearti  which 
surrounds  die  filaments,  and  die  latter  dispose  diem- 
selves  so  as  to  form  a  single  thread.  This  chromatic 
filament,  which  has  now  become  a  single  thread,  is 
shortened  as  it  thickens  spircmf\  /  it  is  then  cut  into 
segments,  twelve  or  twenty-four  in  die  case  of  animak 
and  a  larger  number  in  die  case  of  plants.  These 
are  chromosomes,  or  xmdeaar  sfgmaUs,  or  chromatic 
loops.  Their  part  is  a  very  important  one.  They 
are  constant  in  number  and  permanent  during  die 
whole  of  die  life  of  die  cell  Let  us  add  tiiat  die 
nucleus  still  contains  accessory  elements  (nndeoli}, 

The  Role  of  the  Nmdems. — Experiment  has  shown 
tiiat  die  nucleus  presides  over  die  nutrition,  die 
growtix,  and  die  conservation  of  die  celL  If,  following 
die  example  of  Balbiani  Gruber,  Xussbaum,  and 
W.  Ronx  of  Leipzig,  we  cut  into  two  a  cell  without 
injuring  die  nucleus,  die  fragment  which  is  denuded 
of  die  nucleus  continues  to  perform  its  functions  for 
some  time  in  die  ordinary  manner,  and  in  some 
**ramn*  in  virtue  of  its  former  impulse.  It  then 
declines  and  dies.  On  die  contrary,  die  fragment 
provided  with  die  nucleus  repairs  its  'wound,  is 
reconstituted  and  continues  to  live.  Thus  die  nucleus 
takes  a  very  remarkable  part  in  the  reproduction  of 
die  cell,  but  it  is  still  a  matter  of  uncertainty  whether 
its  role  is  here  subordinated  to  tiiat  of  die  cellular 
body,  or  if  it  is  pre-eminent.  However  that  may  be, 
it  follows  from  diis  experiment  tiiat  die  nucleus 
presents  all  the  characteristics  of  a  vigorous  vitality, 


l66  LIFE    AND    DEATH. 

and  that  it  is  in  its  protoplasm  that  the  chemists 
should  be  able  to  find  the  compounds,  the  special 
albuminoids,  which,  par  excellence,  form  living  matter. 


§  3.  THE  PHYSICAL  CONSTITUTION  OF  LIVING 
MATTER.    THE  MICELLAR  THEORY. 

Physical  Constitution  of  Living  Matter. — Micro- 
scopic examination  does  not  take  us  much  farther. 
The  microscope,  with  the  strongest  magnification 
of  which  it  is  capable  at  present,  shows  us  nothing 
beyond  these  links  of  aligned  microsomes  forming 
the  species  of  protoplasmic  thread  or  mitome,  whose 
cellular  body  is  a  confused  tangle  or  a  very  tangled 
ball.  It  is  not  probable  that  direct  sight  can  pene- 
trate much  farther  than  this.  No  doubt  the  micro- 
scope, which  has  been  so  vastly  improved,  is  capable 
of  still  further  improvement.  But  these  improve- 
ments are  not  indefinite.  We  have  already  reached 
a  linear  magnification  of  2000,  and  theory  tells  us 
that  a  magnification  of  4000  is  the  limit  which  cannot 
be  passed.  The  penetrating  power  of  the  instrument 
is  therefore  near  its  culminating  point.  It  has  already 
given  almost  all  that  we  have  a  right  to  expect 
from  it. 

We  must,  however,  penetrate  beyond  this  micro- 
scopic structure  at  which  the  sense  of  sight  has  been 
arrested.  How  is  this  to  be  done?  When  observa- 
tion is  arrested,  hypothesis  takes  its  place.  Here 
there  are  two  kinds  of  hypotheses,  the  one  purely 
anatomical,  the  other  physical.  Anatomically,  beyond 
the  visible  microsomes  there  have  been  imagined 
invisible  hyper-microscopic  corpuscles,  the  plastidules 


MORPHOLOGICAL   UNITY   OF   LIVING   BEINGS.     167 

of  Haeckel,  the  idioblasts  of  Hertwig,  the  pangenes  of 
de  Vries,  the  plasomes  of  Wiesner,  the  gemmules  of 
Darwin,  and  the  biophores  of  Weismann. 

Biologists  who  have  not  got  all  that  they  hoped 
from  microscopic  structure  are  therefore  thrown  back 
on  hyper-microscopic  structure. 

It  is  very  remarkable  that  all  this  profound  know- 
ledge of  structure  has  been  so  sterile  from  the  point 
of  view  of  the  knowledge  of  cellular  functional  activity. 
All  that  is  known  of  the  life  of  the  cell  has  been 
revealed  by  experiment.  Nothing  has  resulted  from 
microscopic  observation  but  ideas  as  to  configuration. 
When  it  is  a  question  of  giving  or  imagining  an 
explanation  of  vital  facts,  of  heredity,  etc.,  biologists 
unable  to  supply  anything  beyond  the  details  of 
structure  revealed  by  anatomy  have  had  recourse  to 
hypothetical  elements,  gemmules,  pangenes,  bio- 
phores, and  different  kinds  of  determinants. 

Anatomy  never  has  explained  and  never  will  ex- 
plain anything.  "Happy  physicists!"  wrote  Loeb, 
"  in  never  having  known  the  method  of  research  by 
sections  and  stainings !  What  would  have  happened 
if  by  chance  a  steam  engine  had  fallen  into  the  hands 
of  a  histological  physicist?  How  many  thousands  of 
sections  differently  stained  and  unstained,  how  many 
drawings,  how  many  figures,  would  have  been  pro- 
duced before  they  knew  for  certain  that  the  machine 
is  an  engine,  and  that  it  is  used  for  transforming 
heat  into  motion  1" 

The  study  of  physical  properties,  continued  on 
rational  hypotheses,  has  also  thrown  some  light 
on  the  possible  constitution  of  living  matter.  The 
gap  between  microscopical  structure  and  molecular  or 
chemical  structure  has  thus  been  filled. 

12 


l68  LIFE    AND    DEATH. 

The  consideration  of  the  properties  of  turgescence 
and  of  swelling,  which  very  generally  belong  to 
organized  tissues,  and  therefore  to  the  organic 
substance  of  protoplasm,  has  enabled  us  to  obtain 
some  idea  of  its  ultra-microscopic  constitution.  If 
we  wet  a  piece  of  sugar  or  a  morsel  of  salt,  before 
they  are  dissolved  they  absorb  and  imbibe  the  water 
without  sensibly  increasing  their  volume.  It  is  quite 
otherwise  with  a  tissue  (i.e.,  with  a  protoplasm) 
when  weakened  in  water  as  a  preliminary.  The 
tissue,  plunged  into  the  liquid,  absorbs  it,  swells,  and 
often  grows  considerably.  And  this  water  does  not 
lodge  in  the  gaps,  in  pre-existing  lacunar  spaces,  for 
organic  matter  presents  no  gaps  of  this  kind.  It 
does  not  resemble  a  porous  mass  with  capillary 
canals,  such  as  sandstone,  tempered  mortar,  clay,  or 
refined  sugar.  The  molecules  of  water  interpose 
between  and  separate  the  organic  molecules,  thus 
increasing  by  a  sort  of  intussusception  the  intervals 
separating  the  one  from  the  other — molecular  intervals 
escaping  the  senses,  as  do  the  molecules  themselves 
because  they  are  of  the  same  order  of  magnitude. 

Micellar  Theory.  —  While  pondering  over  this 
phenomenon,  an  eminent  physiologist,  Nageli,  was 
led  in  1877  to  propose  his  niicellar  theory.  Micellae 
are  groups  of  molecules  in  the  sense  in  which 
physicists  and  chemists  use  the  word.  They  are 
molecular  structures  with  a  configuration.  They 
rapidly  absorb  water  and  are  capable  of  fixing  a 
more  or  less  thick  and  adherent  layer  of  it  to  their 
surface.  In  a  word,  they  are  aggregates  of  organic 
matter  and  water. 

There  is  therefore  every  reason  for  believing  that 
the  microsomes  of  spongy  protoplasm,  the  physical 


MORPHOLOGICAL    UNITY   OF   LIVING    BEINGS.     169 

support  or  basis  of  cellular  life,  are  groups  of  micella 
formed  of  albuminoid  substances  and  water.  These 
clustered  forms,  these  micellae,  are  not  absolutely 
peculiar  to  organized  matter.  PfefFer,  the  learned 
botanist,  has  pointed  them  out  under  another  name, 
tagmata,  in  the  membranes  of  chemical  precipitates. 

Beyond  this  limit  analysis  finds  nothing  but  the 
chemical  molecule  and  the  atom.  So  that  if  we 
wish  to  reconstruct  the  hierarchy  of  the  materials  of 
constitution  of  the  protoplasm  in  order  of  ascending 
complexity,  xve  shall  find  at  the  foundation  the  atom  or 
atoms  of  simple  bodies.  They  are  principally  carbon, 
hydrogen,  oxygen,  nitrogen,  the  elements  of  all 
organic  compounds,  to  which  may  be  added  sulphur 
and  phosphorus.  At  the  head  we  have  the  albu- 
minoid molecule,  or  the  albuminoid  molecules, 
aggregates  of  the  preceding  atoms.  In  the  third 
stage  the  micellae  or  tagmata,  aggregates  of  albu- 
minoids and  water,  are  still  too  small  to  be  observed 
by  the  senses.  They  unite  in  their  turn  to  form  the 
microsomes,  the  first  elements  visible  to  the  micro- 
scope. The  microsomes,  cemented  by  linin,  form  the 
filaments  or  links  which  are  called  mitomes.  The 
living  protoplasm  is  therefore  nothing  but  a  chain,  or 
tangled  skein,  or  a  spongy  skeleton  formed  by  its 
filaments. 

Such  is  the  typical  constitution  of  living  matter 
according  to  microscopic  observation,  supplemented  by 
a  perfectly  reasonable  hypothesis,  which  is,  so  to  speak, 
only  a  translation  of  one  of  its  most  evident  physical 
properties.  This  relatively  simple  scheme  has  become 
a  complex  scheme  in  the  hands  of  later  biologists. 
On  the  micellar  hypothesis,  which  seems  almost 
inevitable  in  its  character,  new  hypotheses  have  been 


170  LIFE    AND    DEATH. 

grafted,  merely  for  the  sake  of  convenience.  Hence, 
we  are  led  farther  and  farther  from  the  real  truth, 
and  this  is  why,  in  order  to  explain  the  phenomena 
of  heredity,  we  find  ourselves  compelled  to  inter- 
calate hypothetical  elements  between  micella;  and 
the  microsome  in  the  higher  hierarchy  quoted  above — 
gemmules,  pangenes,  plasomes,  which  are  only  mental 
pictures  or  simple  images  to  represent  them. 


§  4.  THE    INDIVIDUALITY    OF   COMPLEX    BEINGS. 
LAW  OF  THE  CONSTITUTION  OF  ORGANISMS. 

Individuality  of  Complex  Beings. — From  the  cellular 
doctrine  follows  a  remarkably  suggestive  conception 
of  living  beings.  The  metazoa  and  the  metaphytes — 
that  is  to  say,  the  multicellular  living  beings  which 
may  be  seen  with  the  eyes  and  do  not  require  the 
microscope  to  reveal  them — arc  an  assemblage  of 
anatomical  elements  and  the  posterity  of  a  cell. 
The  animal  or  the  plant,  instead  of  being  an 
individual  unity,  is  a  "  multitude,"  a  term  which  is 
used  by  Goethe  himself  when  pondering,  in  1807,  over 
the  doctrine  taught  by  Bichat ;  or,  according  to  the 
equally  correct  expression  of  Hegel,  it  is  a  "nation  "  ; 
it  springs  from  a  common  cellular  ancestor,  just  as 
the  Jewish  people  sprang  from  the  loins  of  Abraham. 

We  now  picture  to  ourselves  the  complex  living 
being,  animal  or  plant,  with  its  configuration  which 
distinguishes  it  from  every  other  being,  just  as  a 
populous  city  is  distinguished  by  a  thousand 
characteristics  from  its  neighbour.  The  elements 
of  this  city  are  independent  and  autonomous  for  the 
same  reason  as  the  anatomical  elements  of  the 


MORPHOLOGICAL    UNITY  OF   LIVING    BEINGS.     IJI 

organism.  Both  have  in  themselves  the  means  of 
life,  which  they  neither  borrow  nor  take  from  then- 
neighbours  nor  from  the  whole.  All  these  inhabitants 
live  in  the  same  way.  are  nourished  and  breathe  in 
the  same  manner,  all  possessing  the  same  general 
faculties,  those  of  man;  but  each  has  besides,  his 
profession,  his  trade,  his  aptitudes,  his  talents,  by 
which  he  contributes  to  social  life,  and  by  which  in 
his  turn  he  depends  on  it  Professional  men,  the 
mason,  the  baker,  the  butcher,  the  manufacturer,  the 
artist,  carry  out  different  tasks  and  furnish  different 
products,  the  more  varied,  the  more  numerous  and 
the  more  differentiated,  in  proportion  as  the  social 
state  has  reached  a  higher  degree  of  perfection.  The 
living  being,  animal  or  plant,  is  a  city  of  this  kind. 

LaiL'  of  the  Constitution  of  Organisms. — Such  is 
the  complex  animal.  It  is  organized  like  the  city. 
But  the  higher  law  of  this  city  is  that  the  conditions 
of  the  elementary  or  individual  life  of  all  the  ana- 
tomical citizens  are  respected,  the  conditions  being 
the  same  for  alL  Food,  air,  and  light  must  be 
brought  everywhere  to  each  sedentary  element ;  the 
waste  must  be  carried  off  in  discharges  which  will 
free  the  whole  from  the  inconvenience  or  the  danger 
of  such  debris  ;  and  that  is  why  we  have  the  different 
forms  of  apparatus  in  the  circulatory,  respiratory, 
and  excretory  economy.  The  organization  of  the 
whole  is  therefore  dominated  by  the  necessities  of 
cellular  life.  This  is  expressed  in  the  law  t»f  tlu  con- 
stitution of  organisms  formulated  by  Claude  Bernard. 
The  organic  edifice  is  made  up  of  apparatus  and 
organs,  which  furnish  to  each  anatomical  element 
the  necessary  conditions*  and  materials  for  the  main- 
tenance of  life  and  the  exercise  of  its  activity.  We 


172  LIFE   AND    DEATH. 

now  understand  what  is  the  life,  and  at  the  same 
time  what  is  the  death,  of  a  complex  being.  The 
life  of  the  complex  animal,  of  the  metazoon,  is  of  two 
degrees ;  at  the  foundation,  the  activity  proper  to 
each  cell,  elementary  life,  cellular  life ;  above,  the 
forms  of  activity  resulting  from  the  association  of  the 
cells,  the  life  of  the  whole,  the  sum  or  rather  the 
complex  of  elementary  partial  lives.  There  is  a 
solidarity  between  them  produced  by  the  nervous 
system,  by  the  community  of  the  general  circulatory, 
respiratory  apparatus,  etc.,  and  by  the  free  com- 
munication and  mixture  of  the  liquids  which  con- 
stitute the  media  of  culture  for  each  cell.  We  shall 
have  an  opportunity  of  recurring  to  current  ideas  as 
to  the  morphological  constitution  of  organisms. 


CHAPTER  III. 

THE   CHEMICAL   UNITY  OF   LIVING    BEINGS. 

The  varieties  and  essential  unity  of  the  protoplasm— Its 
affinity  for  oxygen — The  chemical  composition  of  proto- 
plasm—Its characteristic  substances.— §  I.  The  different 
categories  of  albuminoid  substances — Nucleo-proteids— 
Albumins  and  histories  —  Nucleins.— §  2.  Constitution  of 
nucleins. — ^  3.  Constitution  of  histones  and  albumins  — 
Schultzenberger's  analysis  of  albumin — Kossol's  analysis — 
The  hexonic  nucleus. 

THE  chemical  unity  of  living  beings  corresponds  to 
their  morphological  unity. 

T  he  Varieties  and  Essential  Unity  of  the  Proto- 
plasm.— One  esfentfal  feature  of  the  living  being  is 
that  it  is  composed  of  matter  peculiar  to  it,  which  is 
called  living  matter,  or  protoplasm.  But  this  is  a 
somewhat  incorrect  way  of  expressing  the  facts. 
There  is  no  unique  living  matter,  no  single  proto- 
plasm ;  their  number  is  infinite,  there  are  as  many  as 
there  are  distinct  individuals.  However  like  one 
man  may  be  to  another,  we  are  compelled  to  admit 
that  they  differ  according  to  the  substance  of  which 
they  are  constituted.  That  of  the  first  offers  a  certain 
characteristic  personal  to  the  first,  and  found  in  all 
his  anatomical  elements  ;  similarly  for  the  second. 
With  Le  Dantec  we  shall  say  that  the  chemical 
substance  of  Primus  is  not  only  of  the  substance  of 
man,  but  in  all  parts  of  his  body  and  in  all  his  con- 
173 


174  LIFE    AND    DEATH. 

stituent  cells  it  is  the  exclusive  substance  of  Primus; 
and,  in  the  same  way,  the  living  matter  of  another 
individual  Secundus  will  carry  everywhere  his  per- 
sonal impress,  which  differs  from  that  of  Primus. 

But  it  is  none  the  less  true  that  this  absolute 
specificity  is  based  with  certainty  only  on  differences 
which  from  the  chemical  point  of  view  are  exceedingly 
slight.  All  these  protoplasms  have  a  very  analogous 
composition.  And,  if  we  regard  as  negligible  the 
smallest  individual,  specific,  generic,  or  ordinal  varia- 
tions we  may  then  speak  in  a  general  manner  of 
protoplasm  or  living  matter, 

Experiment  shows  us,  in  fact,  that  the  real  living 
substance — apart  from  the  products  it  manufactures 
and  can  retain  or  reject — is  in  every  cell  tolerably 
similar  to  itself.  The  fundamental  chemical  re- 
semblance of  all  protoplasms  is  certain,  and  thus 
we  may  speak  of  their  typical  composition.  We 
may  sum  up  the  work  of  physiological  chemistry  for 
the  last  three  quarters  of  a  century  by  affirming  that 
it  has  established  the  chemical  unity  of  all  living 
beings — that  is  to  say,  a  very  notable  analogy  in  the 
composition  of  their  protoplasm. 

This  living  matter  is  essentially  a  mixture  of  the 
proteid  or  albuminoid  substances,  to  which  may  be 
added  other  categories  of  immediate  principles,  such 
as  carbohydrates  and  fatty  matters.  But  the  latter 
are  of  secondary  importance.  The  essential  element 
is  the  proteid  substance.  The  most  skilful  chemists 
have  tried  for  more  than  half  a  century  to  discover 
its  composition.  Only  during  the  last  few  years 
—  thanks  to  the  researches  of  Kossel,  the  German 
chemist,  following  on  those  of  Schultzenberger  and 
Miescher — we  are  beginning  to  know  the  outer  walls 


THE   CHEMICAL   UNITY   OF  LHTXG   BEINGS.     175 

or  the  framework  of  the  albuminoid  molecule;  in 
other  words,  its  chemical  nucleus. 

Physical  C/tanuters  of  Protoplasm. — About  1860 
Ch.  Robin  thought  that  he  had  defined  living  matter 
sufficiently — or,  at  least,  as  perfectly  as  could  be 
expected  at  that  time — by  attributing  to  it  three 
physical  characteristics.  They  were : — Absence  of 
homogeneity,  molecular  symmetry,  and  the  association 
of  three  orders  of  immediate  principles — albuminoids, 
carbohydrates  and  fats.  These  characteristics  assist, 
but  do  not  suffice,  to  define  the  organization. 

No  doubt  the  characteristics  must  be  completed  by 
the  addition  of  a  certain  number  of  more  subtle 
physical  features. 

One  of  them  refers  to  the  structure  of  protoplasm 
as  revealed  by  the  microscope.  Throughout  the 
whole  of  the  living  kingdom,  from  the  bacteria  studied 
by  Knnstler  and  Busquet  to  the  most  complicated 
protozoa,  protoplasmic  matter  presents  the  same 
constitution,  and  in  consequence,  this  structure  of 
the  protoplasm  must  be  considered  as  one  of  its 
distinctive  characters.  It  is  not  homogeneous;  it 
is  not  the  last  term  of  the  visible  organization :  it  is 
itself  organized.  Experiment  shows  that  it  does  not 
resist  breaking  up  or  crushing.  Mutilations  cause 
it  to  lose  its  properties.  As  for  the  kind  of  structure 
that  it  presents,  it  may  be  expressed  by  saying  that  it 
is  that  of  a  foamy  emulsion. 

We  saw  above  that  our  knowledge  as  to  the  physical 
condition  of  protoplasm  has  been  completed  by  the 
theories  of  Biitschli's  micellae  or  Pfeffer's  tagmata. 

Properties  of  the  Protoplasm.  Its  Affinity  for 
Oxygen. — From  the  chemical  point  of  view,  living 
matter  presents  a  very  remarkable  property — namely. 


176  LIFE    AND    DEATH. 

a  great  affinity  for  oxygen.  It  absorbs  it  so  greedily 
that  the  gas  cannot  remain  in  a  free  state  in  its 
neighbourhood.  Living  protoplasm,  therefore,  exer- 
cises a  reducing  power.  But  it  does  not  absorb 
oxygen  in  this  way  for  its  own  advantage  ;  oxygen 
is  not  absorbed,  as  was  supposed  thirty  years  ago,  to 
supply  fuel  wherewith  to  burn  the  protoplasm.  The 
products  are  not  those  of  its  oxidation,  of  its  own 
disintegration.  They  are  the  products  of  combustion 
of  the  reserve-stuff  which  is  incorporated  in  it. 
These  substances  have  been  supplied  to  it  from 
without,  like  the  oxygen  itself,  with  the  blood.  This 
was  proved  by  G.  Pfltiger  in  1872  to  1876.  The 
protoplasm  is  only  the  focus,  the  scene,  or  the 
factor  of  combustion.  It  is  not  its  victim,  it  does 
not  itself  furnish  the  fuel.  It  works  like  the  chemist, 
who  obtains  a  reaction  with  the  substances  that  are 
given  to  him. 

As  for  the  reducing  power  of  protoplasm,  A. 
Gautier  in  1881  and  Ehrlich  in  1890  have  given  fresh 
proofs.  A.  Gautier  in  particular  has  insisted  that  the 
phenomena  of  combustion  take  place,  so  to  speak, 
outside  the  cell,  and  at  the  expense  of  the  products 
which  surround  it ;  while  on  the  contrary  the  really 
active  and  living  parts  of  the  nucleus  and  of  the 
cellular  body,  work  protected  by  the  oxygen,  as  in  the 
case  of  anaerobic  microbes. 

This  result  is  of  great  importance.  Burdon  Sander- 
son, the  late  learned  professor  of  physiology  at  the 
University  of  Oxford,  has  not  hesitated  to  compare 
it  to  the  discovery  of  respiratory  combustion  by 
Lavoisier.  There  is  no  doubt  some  exaggeration  in 
the  comparison ;  but  there  is,  on  the  other  hand,  no 
less  exaggeration  in  supposing  that  it  is  not  of  great 


THE   CHEMICAL   U3OTY  OF   LIVING   BEINGS.     177 

importance.  We  may  no  longer  in  these  days  speak 
without  reservation  of  the  vital  vortex  of  Cuvier,  and 
of  the  incessant  twofold  movement  of  assimilation 
and  dissimilation  which  is  ever  destroying  living 
matter  and  building  it  up  again.  In  reality,  the 
living  protoplasm  varies  very  little;  it  only  under- 
goes oscillations  of  very  slight  extent;  it  is  the 
materials,  the  reserve  stuff  on  which  it  operates,  which 
are  subject  to  continual  transformations. 

Chtmual  Composition  of  Protoplasm. — One  of  the 
the  three  characters  attributed  by  Ch.  Robin  to  living 
matter  was  its  chemical  composition,  of  which  little 
was  known  in  his  time.  He  insisted  on  the  constant 
presence  in  the  living  elements  of  three  orders  of 
immediate  principles — proteid  substances,  carbo- 
hydrates, and  fatty  bodies.  In  reality  die  proteid 
substances,  or  albuminoids,  alone  are  characteristic. 
The  two  other  groups,  carbohydrates  and  fatty  bodies, 
are  rather  the  signs  and  the  products  of  the  vital 
activity,  than  constituents  of  the  matter  on  which  it  is 
exercised. 

It  is  therefore  on  the  knowledge  of  the  proteid 
substances  that  all  the  sagacity  of  biological  chemists 
has  been  exercised.  Their  efforts  for  thirty  years, 
and  particularly  in  the  last  few  years,  have  not  been 
barren ;  they  enable  us  to  give  a  first  rough  sketch  of 
the  constitution  of  these  substances. 

§  i.  THE  CHARACTERISTIC  SUBSTANCES  OF  THE 
PROTOPLASM.    THE  NUCLEO-PROTEIDS. 

The  Different  Categories  of  Albuminoid  Substances. 
— Albuminoid  or  proteid  substances  are  extremely 
complex  compounds,  much  more  so  than  any  of  those 


178  LIFE   AND   DEATH. 

which  are  being  constantly  studied  by  the  chemist. 
They  also  are  to  be  found  in  great  variety.  It  has 
been  difficult  to  separate  them  one  from  the  other,  to 
characterize  them  rigorously,  or,  in  other  words,  to 
classify  them.  However,  it  has  been  done  now,  and 
we  distinguish  three  classes  which  are  differentiated 
at  once  from  the  physiological  and  from  the  chemical 
points  of  view.  The  first  comprises  the  complete  or 
typical  albuminoids.  They  are  the  proteids  or  nnclco- 
albuminoids.  They  are  to  be  found  in  the  most  active 
and  most  living  parts  of  the  protoplasm,  and  therefore 
in  the  spongioplasm  of  the  cell  and  around  the 
nucleus.  The  second  group  is  formed  of  albumins 
and  globulins,  compounds  already  simpler,  fragments 
derived  from  the  destruction  of  the  preceding,  into 
which  they  enter  as  constituent  elements.  In  the 
isolated  state  they  do  not  belong  to  the  really  living 
protoplasm;  they  exist  in  the  cellular  juice,  in  the 
interstitial  and  circulating  liquids  in  the  blood  and  in 
the  lymph.  The  third  category  comprises  real  but 
incomplete  albuminoids.  They  are  to  be  found  in 
the  portions  of  the  economy  which  have  a  specialized 
or  attenuated  life,  and  are  destined  to  serve  as  a 
support  to  the  more  active  elements — i.e.,  they  con- 
tribute to  the  building  up  of  the  bony,  cartilaginous, 
conjunctive,  elastic  tissues.  They  are  called  allnt- 
moids.  It  is  naturally  the  first  group,  that  of  the 
proteids — i.e.,  of  the  complete  and  characteristic  com- 
pounds of  the  living  substance — upon  which  the 
attention  of  the  physiologists  must  be  fixed.  It  is 
only  quite  recently  that  the  clear  definition  of  these 
substances  has  been  given,  and  proteid  compounds 
detected  in  the  confused  mass. 

TJie  Nudeo-proteids. — This   progress   in    the    char- 


THE   CHEMICAL   UNITY   OF    LIVING    BEINGS.     I/Q 

acterization  and  specification  of  the  proteids  required 
in  the  first  place  a  knowledge  of  two  particular  com- 
pounds, the  nucleins  and  the  liistoms.  This  did  not 
become  possible  until  after  the  researches  of  Miescher 
and  Kossel  on  the  nucleins,  which  went  on  from  1874 
to  1892,  and  those  of  Lilienfeld  and  d'Yvor  Bang  on 
the  histpnes,  from  1893  to  l899-  The  complete 
albuminoids  are  constituted  by  the  combination  of 
two  kinds  of  substances — albumins  or  histones  on  the 
one  hand,  and  nucleins  on  the  other.  By  combining 
solutions  of  albumins  or  histones  with  solutions  of 
nuclein,  the  synthesis  of  the  proteid  is  effected.  The 
study  of  the  properties  and  characteristics  of  these 
nucleo-albumins  and  nucleo-histones  is  going  on  at 
the  present  moment  It  is  being  carried  out  with 
much  method  and  with  wonderful  patience  by  the 
German  school. 

All  the  proteids  contain  phosphorus  in  addition  to 
the  five  chemical  elements,  carbon,  oxygen,  hydrogen, 
nitrogen,  and  sulphur,  which  are  common  to  the 
other  albuminoids.  Another  interesting  feature  in 
their  history  is  that  the  action  of  the  gastric  juice 
divides  them  into  their  two  constituents : — the  nuclein, 
which  is  deposited  and  resists  the  destructive  action 
of  the  digestive  liquid,  and  the  albumin  or  histonc, 
which  on  the  contrary  experiences  this  action  with 
the  usual  consequences.  Thus  the  gastric  juice 
furnishes  a  process  which  is  very  simple  and  very 
convenient  in  the  analysis  of  the  proteids. 

Localisation  of  tlu  Nudeo- Proteids. — What  we  said 
before  as  to  the  important  physiological  role  of  the 
cellular  nucleus  may  arouse  the  expectation  that  in  it 
will  be  found  the  living  matter  which  is  chemically 
the  most  differentiated,  the  albuminoids  of  highest 


l8o  LIFE    AND    DEATH. 

rank — i.e.,  the  nucleo-proteids  and  their  constituents. 
Not  that  they  would  not  be  found  in  the  protoplasm 
of  the  rest  of  the  cell,  but  there  is  certainly  a  risk 
that  they  would  be  less  concentrated  there  and  more 
blended  with  accessory  products ;  they  are  there  con- 
nected with  much  more  secondary  vital  functions. 
This  conclusion  inspired  the  early  researches  of  Pro- 
fessor Miescher,  of  Basle,  in  1874,  and,  twenty  years 
later,  those  of  Professor  Kossel,  one  of  the  most 
eminent  physiological  chemists  in  Germany. 

In  fact,  these  compounds  have  been  found  in  all 
tissues  which  are  rich  in  cellular  elements  with  well- 
developed  nuclei.  The  white  globules  of  the  blood 
furnished  to  Lilienfeld  the  first  nucleo-histone  ever 
isolated.  The  red  globules  themselves,  when  they 
possess  a  nucleus,  which  is  the  case  in  birds  and 
reptiles  as  well  as  in  the  embryo  of  mammals,  contain 
a  nucleo-proteid  which  was  easily  isolated  by  Plosz  and 
Kossel.  Hammarsten,  the  Swedish  chemist,  who  has 
acquired  a  great  reputation  from  his  researches  in 
other  domains  of  biological  chemistry,  prepared  the 
nucleo-proteids  of  the  pancreas  in  1893.  They  have 
been  obtained  from  the  liver,  from  the  thyroid 
gland  (Ostwald),  from  brewers'  yeast  (Kossel),  from 
mushrooms,  and  from  barley  (Petit).  They  have 
been  detected  in  starchy  bodies  and  in  bacteria 
(Galeotti). 


§  2.  CONSTITUTION  OF  NUCLEINS. 

Constitution  of  Nucleins. — Our  path  is  already 
marked  out  if  we  wish  to  penetrate  farther  into  the 
constitution  of  these  proteids;  which  are  the  imme- 


THE    CHEMICAL   UNITY   OF   LIVING    BEINGS.     l8l 

diate  principles  highest  in  complexity  among  those 
which  form  the  living  protoplasm.  We  must  analyze 
the  two  components,  the  albumins  and  the  histones  on 
the  one  hand,  and  the  nucleins  on  the  other.  As  for 
the  nucleins,  this  has  already  been  done,  or  very 
nearly  so. 

Kossel,  in  fact,  decomposed  the  nuclein  by  a  series 
of  very  carefully  arranged  operations,  and  has  reduced 
it  step  by  step  to  its  crystallizable  organic  radicals. 
At  each  stage  that  we  descend  in  the  scale  of 
simplification  a  body  appears  which  is  more  acid  and 
more  rich  in  phosphorus.  At  the  third  stage  we 
come  to  phosphoric  acid  itsel£  The  first  operation 
divides  the  nuclein  into  two  substances:  the  new 
albumin  and  nucleinic  acid.  After  separating  these 
elements  they  can  be  reunited :  a  solution  of  albumin 
with  a  solution  of  nucleinic  acid  reconstitutes  the 
nuclein.  A  second  operation  separates  the  nucleinic 
acid  in  its  turn  into  three  parts.  One  is  a  body  of 
the  nature  of  the  sugars — /.*.,  a  carbohydrate.  The 
appearance  of  a  sugar  in  this  portion  of  the  molecule 
of  nucleinic  acid  is  an  interesting  fact  and  fertile  in 
results.  The  second  part  is  constituted  by  a  mixture 
of  nitrogenous  bodies,  well  known  in  organic  chemistry 
under  the  name  of  xantJiic  bases  (xanthin,  hypo- 
xanthin,  guanin,  and  adenin).  The  third  part  is  a 
very  acid  body  and  full  of  phosphorus — thymic  acid. 
If  in  a  third  and  last  operation  the  thymic  acid  is 
analyzed,  it  is  finally  separated  into  phosphoric  acid 
and  into  thymene,  a  crystallizable  base,  and  thus  we 
are  brought  back  to  the  physical  world,  for  all  these 
bodies  incontestably  belong  to  it 


182  LIFE    AND    DEATH. 


§  3.  THE  CONSTITUTION  OF  HISTONES  AND 
ALBUMINS. 

Constitution  of  Histones. — But  we  are  only  half-way 
through  our  task.  We  are  acquainted  in  its  origin 
with  one  of  the  genealogical  branches  of  the  proteid, 
the  nucleinic  branch.  We  must  also  learn  something 
of  the  other  branch,  the  albumin  or  histone  branch. 
But  on  this  side  the  problem  assumes  a  character  of 
difficulty  and  complexity  which  is  admirably  adapted 
to  discourage  the  most  untiring  patience. 

The  analysis  of  albumin  for  a  long  time  baulked 
the  chemist.  "  Here,"  said  Danilewsky,  "we  come  to 
a  closed  door  which  resists  all  our  efforts."  We  know 
how  vastly  interesting  what  is  taking  place  on  the 
other  side  must  be,  but  we  cannot  get  there.  We  get 
a  mere  glimpse  through  the  cracks  or  chinks  which 
we  have  been  able  to  make. 

This  analysis  of  albuminous  matter  at  first  requires 
great  precautions.  The  chemist  finds  himself  in  the 
presence  of  architecture  of  a  very  subtle  kind.  The 
molecule  of  albumin  is  a  complex  edifice  which  has 
used  up  several  thousand  atoms.  To  perceive  the 
plan  and  structure,  it  must  be  dismantled  and 
separated  into  parts  which  are  neither  too  large  nor 
too  small.  Such  careful  demolition  is  difficult. 
Processes  too  rough  or  too  violent  will  reduce  the 
whole  to  the  tiniest  of  fragments.  It  is  a  statue 
which  may  be  reduced  to  dust,  instead  of  being 
separated  into  recognizable  fragments,  easily  fitted  in 
place  along  their  fractured  faces. 

Analysis  of  Albumin  by  Schiitzenberger. — Schutzen- 
berger,  a  chemist  of  great  merit,  attempted  (about 


THE    CHEMICAL    UNITY   OF   LIVING    BEINGS.     183 

1875)  this  thankless  task.  Others  before  him  had 
experimented  in  various  ways.  Two  Austrian 
scientists,  Hlasitwetz  and  Habermann,  in  1873,  an<^ 
a  little  later  Drechsel  in  1892,  had  used  concen- 
trated hydrochloric  acid  to  break  down  albumin. 
They  also  employed  bromine  for  the  same  purpose. 
More  recently  Fuerth  had  used  nitric  acid  with  a 
similar  object.  Schiitzenberger  tried  another  way. 
The  battering  ram  which  he  used  against  the  edifice 
of  albumin  was  a  concentrated  alkali,  baryta.  He 
warmed  the  white  of  an  egg  with  barium  hydrate 
in  a  closed  vessel  at  a  temperature  of  2CO3.  The 
albumin  of  egg  then  divides  into  a  certain  number  of 
simpler  groups.  The  difficulty  is  to  isolate  and  to 
recognize  each  part  in  this  mass  of  the  materials  of 
demolition.  That  can  be  done  by  the  aid  of  the 
processes  of  direct  analysis.  By  mentally  combining 
these  different  fragments,  the  original  building  is 
reconstructed.  This  method  of  demolition  is  certainly 
too  rough  and  violent  Schiitzenberger's  operation 
gives  us  very  fine  fragments — small  molecules  of  free 
hydrogen,  of  ammonia,  of  carbonic,  acetic,  and  oxalic, 
acids  which  reveal  extreme  pulverization.  These 
products  represent  about  a  quarter  of  the  total  mass. 
The  other  three-quarters  are  formed  of  larger  frag- 
ments, the  examination  of  which  is  most  instructive. 
They  belong  to  four  groups.  The  first  comprises  five 
or  six  bodies,  amido-acids  or  leucins.  It  proves  the 
existence  in  the  molecule  of  albumin  of  compounds  of 
the  series  of  fats — />.,  arranged  in  an  open  chain. 
The  second  group  is  formed  by  tyrosin  and  kindred 
products — i.e.,  by  the  bodies  of  the  aromatic  series, 
which  force  us  to  acknowledge  the  presence  in  the 
molecule  of  albumin  of  a  benzene  nucleus.  The  third 

13 


184  LIFE   AND   DEATH. 

group  forms  around  the  nucleus  known  to  chemists 
under  the  name  of  pyrrol.  The  fourth  comprises 
bodies  such  as  the  glucoproteins,  connected  with  the 
sugars,  or  carbohydrates. 

Does  the  fact  that  the  molecule  of  albumin  is 
destroyed  in  producing  these  compounds  raise  the 
question  as  to  whether  it  implies  the  idea  that  in 
reality  they  pre-exist  in  it?  Chemists  are  rather 
inclined  to  admit  this.  However,  the  conclusion  does 
not  appear  to  be  permissible.  Duclaux  considers  it 
doubtful.  It  is  not  certain  that  all  these  fragmentary 
bodies  pre-exist  in  reality,  and  it  is  no  more  certain 
that  a  simple  bringing  of  them  together  represents 
the  primitive  edifice.  Materials  of  demolition  from  a 
house  that  has  been  pulled  down  give  no  idea  of  its 
natural  architectural  character.  There  is  only  one 
way  of  justifying  the  hypothesis,  and  that  is  to  re- 
constitute the  original  molecule  of  albumin  by  bring- 
ing the  fragments  together.  We  have  not  got  to  that 
stage  yet.  The  era  of  syntheses  of  such  complexity 
is  more  or  less  near,  but  it  has  certainly  not  yet 
begun. 

Moreover,  it  is  not  correct  to  say  that  the  simple 
juxtaposition  of  the  surfaces  of  fracture  will  reproduce 
the  initial  body.  The  fragments,  so  far  as  analysis 
has  obtained  them,  are  not  absolutely  what  they  might 
have  been  in  the  original  structure.  There  they 
adhered  the  one  to  the  other,  not  only  by  the  mere 
contact  of  their  surfaces  of  fracture,  as  is  supposed, 
but  in  a  slightly  more  complex  manner.  The  frag- 
ments of  the  molecule  are  joined  by  bonds.  V/e  can 
picture  them  to  ourselves  by  supposing  these  bonds 
to  be  like  hooks.  The  hooks,  which  could  only  be 
broken  by  violence,  are  called  by  the  chemists 


THE   CHEMICAL   UNITY  OF   LIVING   BEINGS.     185 

satisfied  atomicities.  These  atomicities,  set  free  by 
the  breaking  up,  cannot  remain  in  this  condition ; 
they  must  be  satisfied  anew.  The  hook  tries  to  attach 
itself.  In  Schiitzenberger's  experiment  the  addition 
of  \vater  provides  for  this  necessity.  A  molecule  of 
water  (H?O)  splits  into  two,  the  hydrogen  (H)  on  the 
one  side  and  the  hydroxyl  (OH)  on  the  other.  These 
two  elements  cling  to  the  liberated  bonds  of  the 
fragments  of  the  molecule  of  albumin,  and  thus 
the  bodies  were  found  complete.  Schiitzenberger's 
experiment,  was  too  violent,  too  radical,  and  it  gave 
too  large  a  number  of  fragments,  with  their  free  hooks 
and  atomicities  unsatisfied,  for  rather  a  large  pro- 
portion of  the  water  added  disappeared  during  the 
experiment  In  one  case  this  quantity  was  as  much 
as  17  grammes  per  100  grammes  of  albumin.  The 
molecules  of  this  water  were  employed  in  the 
reparation  of  the  incomplete  fragmentary  molecules 
of  the  albumin. 

It  follows  that  Schiitzenberger's  experiment  gave 
too  large  a  number  of  very  small  pieces  corresponding 
to  far  too  great  a  pulverization.  The  very  small  frag- 
ments are  the  molecules  of  acids  such  as  acetic  acid, 
oxalic  acid,  carbonic  acid,  molecules  of  ammonia, 
and  even  of  hydrogen,  which  we  know  we  are  setting 
free. 

But,  apart  from  these  products  which  represent  a 
quarter  of  the  molecule  of  albumin  submitted  to 
analysis,  the  other  three  quarters  represent  larger 
fragments  which  may  be  considered  as  the  real 
constituents  of  the  building.  Thus  we  find  four 
kinds  of  groups  which  may  be  accepted  as  natural 
The  first  of  these  groups  is  that  of  the  leucins  or 
amido-acids.  It  proves  the  existence  in  the  molecule 


l86  LIFE    AND    DEATH. 

of  albumin  of  compounds  of  the  fatty  series.  There 
is  also  an  aromatic  group — a  pyridine  group — and  a 
group  belonging  to  the  category  of  sugars.  Imagine 
a  certain  grouping  of  these  four  series.  This  would 
be  the  nucleus  of  the  molecule  of  albumin.  If  we 
graft  on  to  this  nucleus,  on  to  this  framework  as  it 
were,  so  many  annexes,  or  lateral  chains,  the  building 
will  be  loaded  with  embellishments  ;  it  will  have 
been  made  unstable  and  ipso  facto  appropriate  for  the 
part  that  it  plays  in  the  incessant  transformations 
of  the  organism. 

Kossefs  Analysis.  Hexonic  Nucleus. — Kossel  has 
approached  the  problem  in  another  fashion.  He 
did  not  attempt  to  attack  the  albumin  of  the  egg. 
This  body  is,  in  fact,  a  heterogeneous  mixture  as 
complex  as  the  needs  of  the  embryo  of  which  it  forms 
the  food.  Kossel  tried  a  physiologically  simpler 
albuminoid.  He  got  it  from  an  anatomical  element 
having  no  nutritive  role,  of  a  very  elementary 
organization  and  physiological  functional  activity, 
and  yet  one  of  energetic  vitality — the  male  generating 
cell.  Instead  of  the  hen's  egg  he  therefore  analyzed 
the  milt  of  fish,  and,  in  the  first  place,  of  salmon.  As 
was  to  be  expected  from  what  has  been  said  of  the 
proteids,  this  living  matter  gives  a  combination  of 
the  nuclein,  already  known,  with  an  albumin.  The 
latter  is  abundant,  forming  a  quarter  of  the  total 
mass.  Its  reaction  is  strongly  alkaline,  which  is  the 
general  characteristic  of  the  variety  of  albumin  known 
by  the  name  of  histones.  Miescher,  the  learned 
chemist  of  Basle,  who  had  noticed  this  basic  albumin 
when  working  on  the  Rhine  salmon,  gave  it  the  name 
of  protamin.  This  is  the  substance  submitted  by 
Kossel  to  analysis  in  preference  to  the  albumin  of 


THE    CHEMICAL    UNITY   OF    LIVING    BEINGS.     187 

egg,  so  dear  to  the  chemists  who  had  preceded  him. 
The  disintegration  of  this  molecule,  instead  of  giving 
the  series  of  bodies  obtained  by  Schutzenberger, 
gave  but  one,  a  real  chemical  base,  arginin.  At  the 
first  trial  the  albumin  examined  was  reduced  to  a 
simple  crystallizable  element  The  conclusion  was 
obvious.  The  protamin  of  salmon  is  the  simplest  of 
albumins.  To  form  this  elementary  proteid  substance 
a  hexonic  base  with  water  is  all  that  is  required. 

Continuing  on  these  lines  other  male  generating 
cells  were  examined  and  a  series  of  protamines  con- 
structed on  the  same  type  was  found,  and  these 
albuminous  bodies  proved  to  be  formed  of  a  base  or 
mixture  of  analogous  hexonic  bases :  arginin,  histi- 
din,  and  lysin — all  bodies  closely  akin  in  their  pro- 
perties and  entirely  belonging  to  the  physical  world. 

Once  aware  of  the  existence  of  this  fundamental 
nucleus,  chemists  found  it  in  the  more  complex 
albumins  where  it  had  been  missed.  It  was  found  in 
the  albumin  of  egg  hidden  under  the  mass  of  other 
groups.  It  was  recognized  in  all  animal  or  vegetable 
albumins.  The  nuclei  of  Schutzenberger  may  be 
missing.  Hexonic  bases  are  the  constant  and 
universal  element  of  all  varieties  of  albumins.  They 
prevail  in  the  chemical  nucleus  of  the  albuminous 
molecule,  and  perhaps  as  is  suggested  by  Kossel, 
they  may  form  it  exclusively.  All  the  other  elements 
are  superadded  and  accessory.  The  essential  type  of 
this  molecular  edifice,  sought  for  so  long,  is  known  at 
last 

Conclusion. — To  sum  up,  the  chemical  unity  of 
living  beings  is  expressed  by  saying  that  living 
matter,  protoplasm,  is  a  mixture  or  a  complex  of 
proteid  substances  with  an  hexonic  nucleus. 


CHAPTER  IV. 

THE   TWOFOLD   CONDITIONING   OF   VITAL 
PHENOMENA.      IRRITABILITY. 

Appearance  of  internal  activity  of  the  living  being — Vital 
phenomena  regarded  as  a  reaction  of  the  ambient  world. — 
§  I.  Extrinsic  conditions— The  optimum  law.— §  2.  Intrinsic 
conditions — The  structure  of  organs  and  apparatus— How 
experiment  attacks  the  phenomena  of  life.  Generalization 
of  the  law  of  inertia — Irritability. 

Instability.  Mutability.  The  Appearance  of  Internal 
Activity  of  the  Living  Being. — One  of  the  most 
remarkable  characteristics  of  the  living  being  is  its 
instability.  It  is  in  a  state  ofjpntinual  change.  The 
simplest  of  the  elementary  beings,  the  plastid,  grows 
and  goes  on  growing  and  becoming  more  complex, 
until  it  reaches  a  stage  at  which  it  divides,  and  thus 
rejuvenated  it  commences  the  upward  march  which 
leads  it  once  again  to  the  same  segmentation.  Its 
evolution  is  thus  betrayed  by  its  growth,  by  the 
variations  of  form  which  correspond  to  it,  and  by 
its  divisjpn. 

If  it  be  a  question  of  beings  higher  in  organiza- 
tion than  the  cellular  element  the  evolutionary- 
character  of  this  mutability  becomes  more  obvious. 
The  being  is  formed,  it  grows ;  then  in  most  cases, 
after  having  passed  through  the  stages  of  youth  and 
adult  age,  it  grows  old,  declines  and  dies,  and  is 
188 


VITAL  PHENOMENA.  189 

disorganized  after  having  gone  through  what  we  may 
call  an  ideal  trajectory.  This  march  in  a  fixed 
direction  with  its  points  of  departure,  its  degrees,  and 
its  termination,  is  a  repetition  of  the  path  that  the 
ancestors  of  the  living  being  have  already  followed. 

Here,  then,  is  a  characteristic  fact  of  vitality,  or 
rather  there  are  two  facts.  The  one  consists  in  this 
morphological  and  organic  evolution,  the  negation  of 
immutability,  the  negation  6F  tne  indefinite  main- 
tenance of  a  permanent  state  or  form  which  is 
regarded,  on  the  contrary,  as  the  condition  of  inert, 
fixed  stable  bodies,  eternally  at  rest.  The  other 
consists  in  the  repetition,  realized  by  this  evolution, 
of  the  similar  evolution  of  its  ancestors ;  this  is  a 
fact  of  heredity.  Finally,  evolution  is  always  in  a 
cycle — that  is  to  say.  that  it  comes  to  an  end  which 
brings  the  course  of  things  to  their  point  of  departure. 

This  kind  of  internal  activity  of  the  living  being 
is  so  striking,  that  not  only  does  it  serve  us  to 
differentiate  the  living  being  from  the  inert  body, 
but  it  gives  rise  to  the  illusion  of  a  kind  of  internal 
demon,  vital  force,  manifested  by  the  more  or  less 
apparent  acts  of  the  life  of  relation,  of  the  motricity, 
of  the  displacement,  or  by  the  less  obvious  acts  of 
vegetative  life. 

Vital  PJienomena  regarded  as  a  Reaction  of  the 
Ambient  World.  Their  Twofold  Conditioning. — In 
reality,  as  the  doctrine  of  energetics  teaches  us,  the 
phenomena  of  vitality  are  not  the  effect  of  a  purely 
internal  activity.  They  are  a  reaction  of  the  environ- 
ment. "The  idea  of  life,"  says  Auguste  Comte, 
"  constantly  assumes  the  necessary  correlation  of  two 
indispensable  elements  : — an  appropriate  organism 
and  a  suitable  environment.  It  is  from  the  reciprocal 


190  LIFE   AND    DEATH. 

action  of  these  two  elements  that  all  vital  phenomena 
inevitably  result."  The  environment  furnishes  the 
living  being  with  three  things:  —  its  matter,  its 
energy,  and  the  exciting  forces  of  its  vitality.  All 
vital  manifestation  results  from  the  conflict  of  two 
factors  :  the  extrinsic  factor  which  provokes  its 
appearance  ;  the  intrinsic  factor,  the  very  organiza- 
tion of  the  living  body,  which  determines  its  form. 
Bichat  and  Cuvier  saw  in  the  phenomena  of  life  the 
exclusive  intervention  of  a  principle  of  action  entirely 
internal,  checked  rather  than  aided  by  the  universal 
forces  of  nature.  The  exact  opposite  is  true.  The 
protozoan  finds  the  stimuli  of  its  vitality  in  the 
aquatic  medium  which  is  its  habitat.  The  really 
living  particles  of  the  metazoan — that  is  to  say,  its 
cells,  its  anatomical  elements — meet  these  stimuli  in 
the  lymph,  in  the  interstitial  liquids  which  bathe 
them  and  which  form  their  real  external  environ- 
ment. 

Auguste  Comte  thoroughly  understood  this  truth, 
and  has  clearly  expressed  it  in  the  passage  we  have 
just  quoted.  Claude  Bernard  has  fully  developed  it 
and  given  it  its  classical  form. 

In  order  to  manifest  the  phenomena  of  vitality, 
the  elementary  being,  the  protoplasmic  being,  re- 
quires from  the  external  world  certain  favourable 
conditions  ;  these  it  finds  there,  and  they  may  be 
called  the  stimuli,  or  extrinsic  conditions  of  vitality. 
This  being  possesses  no  initiative  or  spontaneity  in 
itself,  it  has  only  a  faculty  of  entering  into  action 
when  an  external  stimulus  provokes  it.  This  sub- 
jtection  of  the  living  matter  is  called  irritability. 
The  term  expresses  that  life  is  not  solely  an  internal 
attribute,  but  an  internal  pjrinc|ple  of  action. 


VITAL   PHENOMENA.  IQI 

§  i.  EXTRINSIC  CONDITIONS. 

Extrinsic  Conditions. — By  showing  that  every  vital 
manifestation  results  from  the  conflict  of  two  factors : 
the  extrinsic  or  physico-chemical  conditions  which 
determine  its  appearance,  and  the  intrinsic  or  organic 
conditions  which  regulate  its  form,  Claude  Bernard 
dealt  a  mortal  blow  at  the  old  vitalist  theories.  For 
he  has  not  only  asserted  the  close  dependence  of  the 
two  kinds  of  factors,  but  he  has  shown  them  in  action 
in  most  physiological  phenomena.  The  study  of  the 
extrinsic  or  physico-chemical  conditions  necessary  to 
vital  manifestations  teaches  us  our  first  truth — 
namely,  that  they  are  not  infinitely  varied  as  might 
be  supposed.  They  present,  on  the  contrary,  a 
remarkable  uniformity  in  their  essential  qualities. 
The  fundamental  conditions  are  the  same  for  the 
animal  or  vegetable  cells  of  every  species.  They  are 
four  in  number  : — moisture^  the  air,  or  rather  oxygen, 
foot,  and  a  certain  chemical  constitution  of  the  medium, 
and  the  last  condition,  the  enunciation  of  which 
seems  vague,  becomes  more  precise  if  we  look  at  it 
a  little  closer.  The  chemical  constitution  of  media 
favourable  to  life,  the  media  of  culture,  obeys  three 
general  laws.  It  is  the  knowledge  of  these  laws 
which  formerly  enabled  Pasteur,  Raulin,  Cohn,  and 
Balbiani  to  provide  the  media  appropriate  to  the 
existence  of  certain  relatively  simple  organisms,  and 
thus  to  create  an  infinitely  valuable  method  for 
the  study  of  nutrition,  etc , — namely,  the  method  of 
artificial  cultures^  numerous  developments  of  which 
have  been  shown  us  by  microbiology  and  physiology". 

The  Optimum  Laze. — It  has  been  saio",  and  it  is 
more  than  a  play  on  words,  that  the  conditions  of 


IQ2  LIFE   AND    DEATH, 

the  vital  medium  were  the  conditions  of  the  juste 
milieu.  Water  is  wanted,  there  must  not  be  too 
much  or  too  little.  Oxygen  is  necessary,  and  also  in 
certain  proportions.  Heat  is  required,  and  for  that, 
too,  there  is  an  optimum  degree.  Certain  chemical 
compounds  are  needed  and,  in  this  respect  too,  there 
must  also  be  optima  proportions. 

Water  is  a  constituent  element  of  the  organisms. 
They  contain  fixed  proportions  for  the  same  tissue, 
proportions  varying  from  one  tissue  to  another 
(between  §  and  T9<y).  The  cell  of  a  living  tissue  re- 
quires around  it  an  aqueous  atmosphere,  formed  by 
the  different  juices  of  the  organism,  the  interstitial 
liquids,  the  blood,  and  the  lymph.  We  are  deceived 
by  appearances  when  we  distinguish 'between  aerial, 
aquatic,  and  land-dwelling  animals,  and  when  we 
speak  of  the  air,  the  water,  and  the  land  as  their 
natural  environment.  If  we  go  to  the  bottom  of 
things,  and  fix  our  attention  on  the  real  living 
unities,  on  the  cells  of  which  the  organism  is  composed, 
we  shall  find  around  them  the  juices,  rich  in  water, 
which  are  their  real  environment.  If  these  juices  are 
diluted  or  concentrated  the  least  in  the  world,  life 
stops.  The  cell,  the  whole  animal,  falls  into  a  state 
of  latent  life,  or  dies.  "  All  living  beings  are  aquatic," 
said  Claude  Bernard.  "  Beings  that  live  in  the  air  are 
in  reality  wandering  aquariums,"  said  another  physio- 
logist. •  "  No  moisture,  no  life,"  wrote  Preyer.  The 
environment  must  contain  water,  but  it  must  contain 
it  in  certain  proportions.  In  the  higher  animals 
there  is  a  mechanism  which  works  automatically  to 
keep  at  a  constant  level  the  quantity  of  water  in  the 
blood.  Researches  on  the  lavage  of  the  blood  (A. 
Dastre  and  Loye)  have  clearly  shown  this. 


VITAL    PHENOMENA.  193 

Oxygen  is  also  necessary  to  life.  It  is  \hepabulum 
vitcs.  But  the  discovery  of  the  beings  called  by 
Pasteur  anacrobia  appears  to  contradict  this  state- 
ment Pfeffer,  the  illustrious  botanist,  was  certain, 
in  1897,  that  the  dogma  of  the  necessity  of  oxygen 
no  longer  held  good.  This  is  no  longer  tenable. 
In  1898  Beijerinck  carried  out  most  careful  re- 
searches on  anaerobia  said  to  have  been  cultivated 
in  a  vacuum,  such  as  the  bacteria  of  tetanus  and  the 
septic  vibrion  ;  or  on  those  to  which  oxygen  seems  to 
be  a  poison,  such  as  the  butyric  and  the  butylic 
ferments,  the  anaerobia  of  putrefaction,  the  reducing 
spirilla  of  the  sulphates.  All  use  free  oxygen.  They 
consume  very  little  it  is  true  ;  they  are  micro-aerobia. 
The  other  organisms,  on  the  contrary,  need  more. 
They  are  macro-aerobia  or  simply  aerobia.  Besides, 
if  the  so-called  anaerobia  take  little  or  no  free 
oxygen,  it  matters  little.  They  take  the  oxygen 
in  combination.  It  may  be  said  with  L.  Errera 
that  they  have  an  affinity  for  oxygen,  for  they 
extract  it  from  its  combinations,  and  that  "  they 
are  so  well  adapted  to  this  mode  of  existence  that 
life  in  the  open  air  being  too  easy  no  longer  suits 
them."  There  are  for  the  different  animal  species 
different  optima  of  oxygen. 

Living  beings  require  a  certain  amount  of  heat. 
Life,  which  could  not  have  existed  on  the  globe  when 
it  was  incandescent,  will  not  be  able  to  exist  when  it 
is  frozen.  For  each  organism  and  each  function 
there  is  a  maximum  and  a  minimum  of  temperature 
compatible  with  activity.  There  is  also  an  optimum. 
For  instance,  the  optimum  is  29*  C  for  the  germination 
of  corn. 

The  condition  of  the  optimum  exists  in  the  same 


194  LIFE   AND    DEATH. 

way  for  the  chemical  composition  of  the  vital  medium 
— and  for  the  other  ambient  physical  conditions,  such 
as  atmospheric  pressure. 

It  is  therefore  a  law  of  universal  scope,  a  regulating 
law,  as  it  were,  of  life.  Life  is  a  function  of  extrinsic 
variables,  water,  air,  heat,  the  chemical  composition  of 
the  medium,  and  pressure.  "  Every  vital  phenomenon 
begins  to  be  produced,  starting  from  a  certain  stage 
of  the  variable  (minimum),  becomes  more  and  more 
vigorous  as  it  increases  up  to  a  determinate  value 
(optimum),  weakens  if  the  variable  continues  to  in- 
crease, and  disappears  when  it  has  reached  a  certain 
limiting  value  (maximum)."  This  law,  proved  by 
Sachs,  the  German  botanist,  in  1860,  apropos  of  the 
action  of  temperature  on  the  germination  of  plants, 
by  Paul  Bert  in  1875,  apropos  of  the  action  of  oxygen 
and  of  atmospheric  pressure  on  animals,  and  already 
formulated  at  that  time  by  Claude  Bernard,  was 
illustrated  by  Leo  Errera  in  1895.  It  is  a  law  of 
moderation.  It  expresses  La  Fontaine's  "  rien  de 
trap"  Terence's  " ne  quid  nimis"  the  (MjSev  ayav  of 
Theognis,  and  the  biblical  phrase  "  omnia  in  mensura 
et  numero  et  pondere"  L.  Errera  sees  the  profound 
cause  of  this  optimum  law  in  the  properties  of  the 
living  protoplasm,  which  are  mean  properties.  It 
is  semi-liquid.  It  is  composed  of  albuminoid  sub- 
stances, which  can  stand  no  extremes  either  from  the 
physical  or  from  the  chemical  points  of  view. 

§  2.  INTRINSIC  CONDITIONS.     THE  LAW  OF  THE 
CONSTITUTION  OF  ORGANS  AND  APPARATUS. 

Laiv  of  the  Constitution  of  Organs  and  Apparatus. — 
If  we    consider    more  highly   organized    beings,  the 


VITAL    PHENOMENA.  IQ5 

influence  of  the  intrinsic  conditions  appears  quite 
as  clearly.  As  we  have  seen,  this  is  so  that  the 
requisite  fundamental  materials  may  be  spent  by 
each  element  in  suitable  proportions, — water,  chemical 
compounds,  air,  and  heat, — that  organs  may  be  added 
to  organs,  and  that  apparatus  may  be  set  to  work  in 
complex  structures.  Why  a  digestive  apparatus? 
To  prepare  and  introduce  into  the  internal  medium 
liquid  materials  which  are  necessary  to  life.  Why  a 
respiratory  apparatus?  To  impart  the  vital  gas 
necessary  to  the  cells,  and  to  expel  the  gaseous 
excrement,  the  carbonic  acid  which  they  reject. 
Why  a  circulatory  apparatus?  To  transport  and 
renew  this  medium  throughout.  The  apparatus,  the 
functional  wheels,  the  vessels,  the  digestive  and 
respiratory  mechanisms  do  not  exist  for  themselves, 
like  the  random  sketches  of  an  artistic  nature.  They 
exist  for  the  innumerable  anatomical  elements  which 
people  the  economy.  They  are  arranged  to  assist 
and  more  rigorously  to  regulate  cellular  life  with 
respect  to  the  extrinsic  conditions  which  it  demands. 
They  are,  in  the  living  body,  as  in  civilized  society, 
the  manufactories  and  the  workshops  which  provide 
for  the  different  members  of  society  dress,  warmth, 
and  food.  In  a  word,  the  law  of  tJie  construction  of 
organisms  or  of  the  bringing  to  perfection  of  an 
organism  is  the  same  as  the  law  of  cellular  life.  It 
is  otherwise  suggestive  as  the  law  of  division  of 
physiological  labour  formerly  enunciated  by  Henry 
Milne-Edwards;  and  in  every  case  it  has  a  more 
concrete  significance.  Finally,  it  brings  the  organic 
functional  activity  into  relation  with  the  conditions  of 
the  ambient  medium. 

How  Experiment  acts  on  the  Phenomena  of  Life. — 


ig6  LIFE    AND   DEATH. 

The  two  orders  of  conditions,  the  one  provided  by  the 
being  itself,  the  other  by  external  agents,  are  equally 
indispensable — and  therefore  of  equal  importance  or 
dignity.  But  they  are  not  equally  accessible  to  the 
experimentalist.  It  is  not  easy  to  exercise  on  the 
organization  direct  and  measurable  actions.  On  the 
contrary,  the  physical  conditions  are  in  the  hands 
and  at  the  discretion  of  the  experimenter.  By  them 
he  may  reach  the  vital  manifestations  as  they  appear, 
stimulate  or  check  them,  defer  or  precipitate  them. 
Thus,  for  instance,  the  physiologist  suspends  or  re- 
establishes at  his  will  full  vital  activity  in  a  multitude 
of  reviviscent  or  hibernating  beings,  such  as  grains, 
the  infusoria  capable  of  encystment,  the  vibrio,  the 
tardigrade,  the  cold-blooded  animals,  and  perennial 
plants. 

The  ambient  world  therefore  furnishes  to  the  animal 
and  to  the  vegetable,  whole  or  fragmentary,  those 
materials  of  its  organization  which  are  at  the  same 
time  the  stimuli  of  its  vitality.  That  is  to  say,  the 
vital  mechanism  would  be  a  dormant  and  inert 
mechanism  if  nothing  in  the  surrounding  medium 
could  provoke  it  to  action  or  give  it  a  check.  It 
would  be  a  kind  of  steam  engine  without  coal  and  fire. 

Living  matter,  in  other  words,  does  not  possess  real 
spontaneity.  As  I  have  shown  elsewhere,  the  law  of 
inertia  which  it  is  supposed  it  obeys  with  inert  bodies 
is  not  special  to  them.  It  is  applied  to  the  living 
bodies  whose  apparent  spontaneity  is  only  an  illusion 
contradicted  by  physiology  as  a  whole.  All  the  vital 
manifestations  are  responses  to  a  stimulus  of  acts 
provoked,  and  not  of  spontaneous  acts. 

Generalization  of  the  Laiv  of  Inertia  in  Living 
Bodies.  Irritability. — In  fact,  vulgar  prejudice  opposes 


VITAL   PHENOMEMA.  197 

this  view.  The  opinion  of  the  average  man  distrusts 
it  It  applies  the  law  of  inertia  only  to  inert  matter. 
This  is  because  the  vital  response  does  not  always 
immediately  succeed  the  external  stimulus,  and  is  not 
always  proportional  to  it  But  it  is  sufficient  to  have 
seen  the  flywheel  of  a  steam  engine  to  understand 
that  the  restitution  of  a  mechanical  force  cannot  be 
instantaneous.  It  is  sufficient  to  have  had  a  finger 
on  the  trigger  of  a  firearm  to  know  that  there  is  no 
necessary  proportion  between  the  intensity  of  the 
stimulus  and  the  magnitude  of  the  force  produced. 
Things  happen  in  the  living  just  as  in  the  inert 
machine. 

The  faculty  of  entering  into  action  when  provoked 
by  an  external  stimulus  has  received,  as  we  have  said, 
the  name  of  irritability.  The  word  is  not  used  of 
inert  matter.  However,  the  condition  of  the  latter  is 
the  same.  But  there  is  no  need  to  affirm  its  irrita- 
bility, because  no  one  denies  it.  We  know  perfectly 
well  that  brute  matter  is  inert,  that  all  the  manifesta- 
tions of  activity  of  which  it  is  the  theatre  are  provoked. 
Inertia  is  for  it  the  equivalent  of  irritability  in  living 
matter.  But  while  it  is  not  necessary  to  introduce 
this  idea  into  the  physical  sciences,  where  it  has 
reigned  since  the  days  of  Galileo,  it  was,  on  the 
contrary,  necessary  to  affirm  it  in  biology,  precisely 
because  it  was  in  biology  that  the  opposing  doctrine 
of  vital  spontaneity  ruled  supreme. 

Such  was  the  view  held  by  Claude  Bernard.  He 
never  varied  on  this  point.  Irritability^  said  he,  is  the 
property  possessed  "  by  every  anatomical  element 
(that  is  to  say,  the  protoplasm  which  enters  into  its 
constitution)  of  being  stimulated  into  activity  and  of 
reacting  in  a  certain  manner  under  the  influence  of 


ig8  LIFE    AND    DEATH. 

the  external  stimuli."  He  could  not  claim  that  this 
was  a  distinguishing  characteristic  between  living 
bodies  and  brute  bodies,  and  that  all  the  less  because 
he  always  tried  to  efface  on  this  point  the  distinctions 
which  were  current  in  his  time,  and  which  were 
established  by  Bichat  and  Cuvier.  And  so  also  Le 
Dantec  does  not  seem  to  have  thoroughly  grasped 
the  ideas  of  the  celebrated  physiologist  on  this  point 
when  he  asserts,  as  if  he  were  thereby  contradicting 
the  opinion  of  Claude  Bernard  and  his  school,  that 
irritability  is  not  something  peculiar  to  living  bodies.1 

1  These  ideas  are  clearly  brought  to  light  in  a  series  of 
articles  in  the  Revue  Philosophique,  published  in  1879  under 
the  title  of  "  La  probleme  physiologiqtie  de  la  vie,"  and  endorsed 
by  A.  Dastre  in  his  commentary  on  the  Plienouienes  comimtns 
aux  animaux  et  aux  plantes. 


CHAPTER  V. 

THE   SPECIFIC   FORM.      ITS   ACQUISITION. 
ITS   REPARATION. 

§  i.  Specific  form  not  special  lo  living  beings — Connected  with 
the  whole  of  the  material  conditions  of  the  body  and  the 
medium — Is  it  a  property  of  chemical  substance?— $  2. 
Acquisition  and  re-establishment  of  the  specific  form- 
Normal  regeneration— Accidental  regeneration  in  the  pro- 
tozoa and  the  plastids — In  the  metazoa. 

§  i.  THE  SPECIFIC  FORM. 

The  Specific  Form  is  not  Peculiar  to  Living  Beings. 
—The  position  of  a  specific  form — the  acquisition  of 
this  typical  form  progressively  realized — the  re-estab- 
lishment when  some  accident  has  altered  it — these 
are  the  features  which  we  consider  distinctive  of  living 
beings,  from  the  protophytes  and  the  lowest  protozoa 
to  the  highest  animals.  Nothing  gives  a  better  idea 
of  the  unity  and  the  individuality  of  the  living  being 
than  the  existence  of  this  typical  form.  We  do  not 
mean,  however,  that  this  characteristic  belongs  to  the 
living  being  alone,  and  is  by  itself  capable  of  defining 
it  We  repeat  that  this  is  not  a  case  with  any 
characteristic  In  particular  the  typical  form  belongs 
to  crystal  as  well  as  to  living  beings. 

T/ie  Specific  Form  depends  on  the  sum  of  Material 
Conditions  of  the  Body  and  the  Medium. — The  con^- 
sideration  of  mineral  bodies  shows  us  form  dependent 
199  14 


200  LIFE    AND    DEATH. 

on  the  physico-chemical  conditions  of  the  body  and 
the  medium.  The  form  depends  mainly  on  physical 
conditions  in  the  cases  of  a  drop  of  water  falling  from 
a  tap,  of  the  liquid  meniscus  in  a  narrow  tube,  of  a 
small  navel-shaped  mass  of  mercury  on  a  marble 
slab,  of  a  drop  of  oil  "emulsioned"  in  a  solution,  and 
of  the  metal  which  is  hardened  by  hammering  or 
annealed.  In  the  case  of  crystals  the  form  depends 
more  on  chemical  conditions.  It  is  crystallization 
which  has  introduced  into  physics  the  idea  that  has 
now  become  a  kind  of  postulate — namely,  that  the 
specific  form  is  connected  with  the  chemical  composi- 
tion. However,  it  is  sufficient  to  instance  the  dimor- 
phism of  a  simple  body,  such  as  sulphur,  sometimes 
prismatic,  sometimes  octahedric,  to  realize  that  sub- 
stance is  only  one  of  the  factors  of  form,  and  that  the 
physical  conditions  of  the  body  and  of  the  medium 
are  other  factors  quite  as  influential. 

Is  the  Specific  Form  a  Property  of  tlie  CJiemical 
Substance  ? — How  much  truer  this  restriction  would 
be  if  we  consider,  instead  of  a  given  chemical  com- 
pound, an  astonishingly  complex  mixture,  such  as 
protoplasm  or  living  matter,  or  the  more  complex 
organism  still — the  cell,  the  plastid. 

Are  there  not  great  differences  between  the  sub- 
stance of  the  cellular  protoplasm,  or  cytoplasmic 
substance,  and  that  of  the  nucleus?  Should  we  not 
distinguish  in  the  former  the  hyaloplasmic  substance; 
the  microsomic  in  the  microsomes;  the  linin  between 
its  granulations ;  the  centrosomic  in  the  centrosome; 
the  archoplasmic  in  the  attraction  sphere;  not  to 
mention  the  different  leucins,  the  vacuolar  juice,  and 
the  various  inclusions?  And  in  the  nucleus  must  we 
not  consider  the  nuclear  juice,  the  substance  of  the 


THE    SPECIFIC    FORM.  2OI 

chromosomes,  and  that  of  the  nucleoles  ?     And  is  not 
each  of  these  probably  a  very  complex  mixture  ? 

However,  it  is  to  this  mixture  that  we  attribute  the 
possession  of  a  form,  in  virtue  of  and  by  extension  of 
the  principles  of  crystallization,  which  definitely  teach 
us  that  these  mixtures  cannot  have  form ;  that  form 
is  the  attribute  of  pure  bodies,  and  is  only  obtained 
by  the  separation  of  the  blended  parts — i.e.,  by  a 
return  to  homogeneity.  There  are  therefore  very 
good  reasons  for  hesitating  before  we  transfer  the 
absolute  principle  of  the  dependence  between 
chemical  form  and  composition,  as  some  philo- 
sophical biologists  have  done,  from  the  physical 
sciences  —  where  it  is  already  subject  to  serious 
restrictions — to  the  biological  sciences. 

Le  Dantec,  however,  has  made  this  principle  the 
basis  of  his  biological  system.  He  therefore  finds  in 
the  crystal  the  model  of  the  living  being.  He  thus 
gives  a  physical  basis  to  life. 

Is  it  a  question  in  this  system  of  explaining  this 
incomprehensible,  this  unfathomable  mystery,  which 
shows  the  egg  cell  attracting  to  itself  materials  from 
without  and  progressively  building  up  that  amazing 
structure  which  is  the  body  of  the  animal,  the  body  of 
a  man,  of  any  given  man,  of  Primus,  for  example? 
It  is  said  that  the  substance  of  Primus  is  specific 
His  living  substance  is  his  own,  special  to  him;  and 
that,  too,  from  the  beginning  of  the  egg  to  the  end  of 
its  metamorphosis.  It  only  remains  to  apply  to  this 
substance  the  postulate,  borrowed  from  crystallo- 
graphy, of  the  absolute  dependence  of  the  nature  of 
substance  on  the  form  it  assumes.  The  form  of  the 
body  of  the  animal,  of  the  man,  of  Primus,  is  the 
crystalline  form  of  their  living  substance-  It  is  the 


202  LIFE   AND    DEATH. 

only  form  of  equilibrium  that  this  substance  can 
assume  under  the  given  conditions,  just  as  the  cube  is 
the  crystallized  form  of  sea  salt,  the  only  state  of 
equilibrium  of  chloride  of  sodium  in  slowly  evaporated 
sea  water.  Thus  the  problem  of  the  living  form  is 
reduced  to  the  problem  of  the  living  substance,  which 
seems  easier;  and  at  the  same  time  the  biological 
mystery  is  reduced  to  a  physical  mystery.  It  is  clear 
that  this  way  of  looking  at  things  simplifies  pro- 
digiously— and,  we  must  add,  simplifies  far  too  much 
— the  obscure  problem  of  the  relation  of  form  to 
substance,  simultaneously  in  the  two  orders  of  science. 
This  may  be  summed  up  in  a  single  sentence: 
There  is  an  established  relation  between  the  specific 
form  and  the  chemical  composition:  the  chemical 
composition  directs  and  implies  the  specific  form. 

We  need  not  now  examine  the  basis  of  this  opinion. 
If  it  is  nothing  but  a  verbal  simplification,  a  unifica- 
tion of  the  language  applied  to  the  two  orders  of 
phenomena,  it  implies  an  assimilation  of  the  mechan- 
isms which  realize  them.  To  the  organogenic  forces 
which  direct  the  building  up  of  the  living  organisms 
it  brings  into  correspondence  the  crystallogenic  forces 
which  group,  adjust,  equilibrate,  and  harmonize  the 
materials  of  the  crystal. 

When  it  is  a  question  of  the  application  of  a 
principle  such  as  this,  in  order  to  test  its  legitimacy 
we  must  always  return  to  the  experimental  founda- 
tions. Let  us  imagine,  for  example,  a  simple  body, 
such  as  sulphur,  heated  and  brought  to  a  state  of 
fusion — that  is  to  say,  homogeneous,  isotropic,  in  an 
undisturbed  medium  the  only  change  in  which  will 
be  a  very  gradual  cooling  down.  These  are  the 
typical  crystallogenic  conditions.  The  body  would 


THE   SPECIFIC   FORM.  203 

take  a  given  crystalline  form.  It  is  from  experiments 
such  as  this  that  we  derive  the  idea  of  a  specific  form 
connected  with  a  chemical  constitution. 

But  in  drawing  this  conclusion  our  logic  is  at  fault. 
The  real  interpretation  suitable  to  this  case,  as  in  all 
others,  is  that  the  specific  form  is  suitable  to  the 
substance,  and  also  to  the  physical,  chemical,  and 
mechanical  conditions  in  which  it  is  placed.  And 
the  proof  is  that  this  same  substance,  sulphur,  which 
takes  the  prismatic  form  immediately  after  fusion, 
will  not  retain  that  form,  but  will  pass  on  to  the 
quite  different  octahedral  form. 

It  is  so  with  the  specific  form  of  the  living  being — 
that  is  to  say,  with  the  assemblage  of  its  constituent 
materials  co-ordinated  in  a  given  system — in  a  word, 
with  its  organization.  This  is  suitable  to  its  sub- 
stance, and  to  all  the  material,  physical,  chemical, 
and  mechanical  conditions  in  which  it  is  placed.  This 
form  is  the  condition  of  material  equilibrium  cor- 
responding to  a  very  complex  situation,  to  a  sum  of 
given  conditions.  The  chemical  condition  is  only 
one  of  these.  And  further,  it  is  hardly  proper  to 
speak  of  a  "  chemical  substance  "  when  we  refer  to  an 
astonishingly  complex  mixture  which  is  in  addition 
variable  from  one  point  to  the  other  of  the  living 
body.  When  we  thus  reduce  phenomena  to  their 
original  signification,  false  analogies  disappear.  To 
say  with  Le  Dantec  that  the  form  of  the  greyhound 
is  the  condition  of  equilibrium  of  the  "greyhound 
chemical  substance "  is  saying  much ;  and  too  much, 
if  it  means  that  the  body  of  the  greyhound  has  a 
substance  which  behaves  in  the  same  way  as  homo- 
geneous, isotropic  masses  like  melted  sulphur  and 
dissolved  salt  It  were  better  to  say  much  less,  if  it 


204  LIFE    AND    DEATH. 

means,  as  it  will  in  the  minds  of  the  physiologists, 
that  the  body  of  the  greyhound  is  the  condition  of 
equilibrium  of  a  heterogeneous,  anisotropic,  material 
system,  subjected  to  an  infinite  number  of  physical 
and  chemical  conditions. 

The  idea  of  connecting  form,  and  by  that  we  mean 
organization,  with  chemical  composition  did  not  arise 
in  the  minds  of  chemists  or  physiologists.  Both  have 
expressed  themselves  very  clearly  on  this  point. 

"We  must  distinguish,"  said  Berthelot,  "between 
the  formation  of  the  chemical  substances,  the  assem- 
blage of  which  constitutes  organized  beings,  and  the 
formation  of  the  organs  themselves.  This  last  problem 
does  not  come  into  the  domain  of  chemistry.  No 
chemist  will  ever  claim  to  have  formed  in  his  laboratory 
a  leaf,  a  fruit,  a  muscle,  or  an  organ.  .  .  .  But  chemistry 
has  a  right  to  claim  that  it  forms  direct  principles — 
that  is  to  say,  the  chemical  materials  which  constitute 
the  organs."  And  Claude  Bernard  in  the  same  way 
writes: — "In  a  word,  the  chemist  in  his  laboratory, 
and  the  living  organism  in  its  apparatus,  work  in  the 
same  way,  but  each  with  its  own  tools.  The  chemist 
can  make  the  products  of  the  living  being,  but  he 
will  never  make  the  tools,  because  they  are  the  result 
of  organic  morphology." 


§  2.  THE  ACQUISITION   AND  RE-ESTABLISHMENT 
OF  THE  SPECIFIC  FORM. 

Acquisition  of  the  Typical  Form. — The  acquisition 
of  the  typical  form  in  the  living  being  is  the  result  of 
ontogenic  work  which  cannot  be  examined  here.  In 
the  elementary  being,  the  plastid,  this  work  is  blended 


THE   SPECIFIC   FORM.  2O5 

with  the  work  of  nutrition.  It  is  directtd  mtlriticm. 
It  consists  of  a  simple  increase  from  the  moment  the 
element  is  born  by  the  division  of  an  anterior  dement; 
and  of  a  necessarily  restricted  differentiation.  It  is  a 
rudimentary  embryogeny.  In  the  complex  being, 
metazoan  or  metaphyte,  the  organism  is  constituted!,, 
starting  from  the  egg,  by  the  growth,  by  the  biporti- 
tion  of  the  elements,  and  their  differentiation,  accom- 
plished in  a  ryrtain  direction  and  in  conformity  with 
a  given  plan.  This,  again,  is  directed  nutrition,  but 
here  the  embryogeny  is  complex.  The  directing  plan 
of  operations  is  no  doubt  the  consequence  of  the 
material  conditions  realized  each  moment  in  the 

~  '  ~  ':.  ".  .  »  ~  . 

Normal  Regeneration. — Not  only  do  living  beings 
themselves  construct  their  typical  architecture,  but 
they  re-establish  it  and  continually  reconstitute  it, 
according  as  accidents,  or  even  ordinary  circumstances, 
tend  to  destroy  it ;  in  a  word,  they  become  rejuvenes- 
cent. This  regeneration  consists  in  the  reformation 
of  the  parrs  that  are  altered  or  carried  away  in  the 
normal  play  of  life,  or  by  the  accidents  which  disturb 
its  course. 

Thus  there  is  a  normal  physiological  regeneration^ 
which  is,  so  to  speak,  the  prolongation  of  the  onto- 
genesis— /.£,  of  the  work  of  fonnation  of  the  individual 
We  have  examples  in  the  reconstitntion  of  the  skin 
of  mammals; — in  the  throwing  off  of  the  epidermic 
products  constantly  used  up  in  their  superficial  and 
*"*ti*f  jMfts  and  regenerated  in  ffc^i**  deeply-seated 
parts;  in  the  loss  and  the  renewal  of  teeth  at  the 
first  dentition  and  in  certain  fish  in  the  fact  of 
successive  dentitions;  in  the  periodical  renewal  of 
the  integument  in  the  larva;  of  insects,  and  in  the 


206  LIFE    AND    DEATH. 

crustaceae;  and  finally  in  the  destruction  and  the 
neo-formation  of  the  globules  of  the  blood  of  verte- 
brates, of  the  glandular  cells,  and  of  the  epithelial 
cells  of  the  intestine. 

Accidental  Regeneration  in  Protozoa  and  Plastids. — 
There  is  also  an  accidental  regeneration  which  more  or 
less  perfectly  renews  the  parts  that  are  lost.  This 
regeneration  has  its  degrees,  from  the  simple  cicatriza- 
tion of  a  wound  to  the  complete  reproduction  of  the 
part  cut  off.  It  is  very  unequally  developed  in 
zoological  groups  even  when  they  are  connected. 
In  the  elementary  monocellular  beings — i.e.,  in  the 
anatomical  elements  and  in  the  protozoa, — the  experi- 
ments in  merotomy,  i.e.,  in  partial  section,  enable  us 
to  appreciate  the  extent  of  this  faculty  of  regenera- 
tion. These  experiments,  inaugurated  by  the  re- 
searches of  Augustus  Waller  in  1851,  were  repeated 
by  Gruber  in  1885,  continued  by  Nussbaum  in  1886, 
Balbiani  in  1889,  Verworn  in  1891,  and  have  been 
reproduced  by  a  large  number  of  observers.  They 
have  shown  that  the  two  fragments  cicatrize,  and  are 
repaired,  building  up  an  organism  externally  similar 
to  the  primitive  organism,  but  smaller.  The  two  new 
organic  units  do  not,  however,  behave  in  the  same 
way.  That  which  retains  the  nucleus  possesses  the 
faculty  of  regeneration,  and  of  living  as  the  primitive 
being  lived.  The  protoplasmic  fragment,  which  does 
not  contain  the  nucleus,  cannot  rebuild  this  absent 
organ;  and  though  it  has  functional  activity  in  most 
respects,  just  as  the  nucleated  fragment,  yet  it  is 
distinguished  from  it  in  others  of  great  importance. 
The  anucleated  fragment  of  an  infusorian  behaves  as 
the  nucleated,  and  as  the  whole  animal  so  far  as  the 
movements  of  the  body,  the  cilia,  prehension  of  food, 


THE   SPECIFIC   FORM.  207 

evacuation  of  faeces,  and  the  rhythmical  contrac- 
tion of  the  pulsatile  vesicules  are  concerned.  But 
Balbiani's  researches  in  1892  have  shown  us  that 
secretion,  complete  regeneration,  and  the  faculty  of 
reproduction  by  fission  can  take  place  only  in  the 
nucleated  fragment — i.e.,  in  the  nucleus. 

Accidental  Reproduction  in  the  Aletazoa. — Among 
multicellular  beings  the  faculty  of  reproduction  is  met 
with  in  the  highest  degree  in  plants,  where  we  find  it 
in  the  process  of  propagation  by  slips.  In  animals  it 
is  the  most  marked  in  Ccelenterata.  Trembley's 
experiments  are  a  striking  instance.  We  know  that 
when  the  hydra  is  cut  into  tiny  pieces  it  reproduces 
exactly  as  many  complete  beings.  Among  the 
worms,  Planaria  afford  a  similar  example.  Every 
fragment,  provided  its  volume  is  not  less  than  a  tenth 
of  that  of  the  whole,  can  reproduce  a  complete,  entire 
being.  The  snail  can  produce  a  large  part  of  its  head, 
including  the  tentacles  and  the  mouth.  Among  the 
Tritons  and  the  Salamanders  the  faculty  of  regenera- 
tion reproduces  the  limbs,  the  tail,  and  the  eye.  In 
the  Frog  family,  on  the  contrary,  the  work  of  re- 
generation does  not  go  beyond  cicatrization,  and  it  is 
the  same  with  Birds  and  Insects. 

It  is  really  startling  to  see  in  a  vertebrate  like  the 
Triton  the  stump  of  an  arm  with  its  fragment  of 
humerus  reproducing  the  forearm  and  the  hand  in  all 
their  complexity,  with  their  skeleton,  blood  vessels, 
nerves,  and  teguments.  We  say  that  the  limb  has 
budded,  as  if  there  were  a  germ  of  it  which  develops 
like  the  seed  of  a  plant,  or  as  if  each  transverse  portion 
of  the  limb,  each  slice,  so  to  speak,  could  re-form  the 
slice  that  follows. 

The  mechanism  of  generation  and  that  of  regenera- 


208  LIFE   AND   DEATH. 

tion  alike  raise  problems  of  the  highest  importance. 
Does  the  part  become  regenerated  just  as  it  was 
formed  at  first  ?  Does  the  regeneration  repeat  the 
ontogeny?  Is  it  true  that  a  lost  organ  is  never  re- 
generated (the  kidney  for  instance)  ?  Does  the 
symmetrical  organ  enjoy  a  compensating  and  hyper- 
trophic  development,  as  Ribbert  has  asserted  ?  And 
further,  if  the  organ  be  removed  and  transplanted  to 
another  position,  can  it  be  grafted  there,  as  Y.  Delage 
maintains?  These  are  very  important  questions;  but 
if  we  dwell  upon  them,  we  shall  be  diverted  from  our 
immediate  object.  Our  task  is  to  look  at  these  facts 
from  the  point  of  view  of  their  significant  and  char- 
acteristic meaning  in  vitality.  Flourens  invoked  on 
their  behalf  the  intervention  of  vital  forces,  plastic 
and  morpJioplastic.  But,  as  we  shall  see  later,  these 
phenomena  of  cicatrization,  of  reparation,  of  re- 
generation, these  more  or  less  complete  efforts  for 
the  re-establishment  of  the  specific  form,  although 
they  are  found  in  all  living  beings  in  different  degrees, 
are  not  exclusively  confined  to  them.  We  find  them 
again  in  some  representatives  of  the  mineral  world — 
in  crystals,  for  instance. 


CHAPTER  VI. 

NUTRITION. 

FUNCTIONAL  ASSIMILATION.  FUNCTIONAL  DESTRUC- 
TION. ORGANIC  DESTRUCTION.  ASSIMILATING 
SYNTHESIS. 

The  extreme  importance  of  nutrition— §  i.  Effect  of  vital 
activity — Destruction  or  growth— Distinction  between  the 
living  substance  and  the  reserve-stuff  mingled  with  it — 
Organic  destruction — Destruction  of  reserve-stuff— De- 
struction of  living  matter — Growth  of  living  matter — 
§  2.  The  two  categories  of  vital  phenomena — Foundations 
of  the  idea  of  functional  destruction — The  two  kinds  of 
phenomena  of  vitality — Criticism  of  Claude  Bernard — 
Current  views — Criticism  of  Le  Dantec's  new  theory  of 
life. — §  3.  Correlation  of  the  two  kinds  of  vital  facts — Law 
of  connection — Contradictions  in  the  new  theory.— §  4.  The 
characteristics  of  nutrition — Its  definition — Its  permanence 
— Erroneous  idea  of  the  vital  vortex— Formative  assimilation 
of  reserve-stuff— Formative  assimilation  of  protoplasm — 
Death,  real  and  apparent. 

The  Immense  Importance  of  Nutrition. — We  new 
come  to  the  important  feature  of  vitality.  All  other 
characteristics  of  living  matter,  its  unstable  equilibrium, 
its  chemical  and  anatomical  organization,  the  acquisi- 
tion and  the  maintenance  of  a  typical  form,  are  only 
secondary  properties,  so  to  speak,  subordinate  with 
reference  to  nutrition.  Generation  itself  is  only  a 
mode.  Nutrition  is  the  essential  attribute  of  life.  It 
is  life  itself. 

209 


210  LIFE   AND   DEATH. 

Before  we  define  it  a  few  preliminary  explanations 
are  necessary. 

The  most  striking  thing  in  living  matter  is  its 
growth.  An  animal,  a  vegetable,  is  something  which 
is  first  more  or  less  minute,  and  which  grows.  Its 
characteristic  is  to  expand — from  the  spore,  the  seed, 
the  slip,  the  egg — it  grows. 

Whether  we  are  dealing  with  a  cellular  element,  a 
plastid,  or  a  complex  being,  their  condition  is  the 
same  in  this  respect.  No  doubt  when  the  animal  or 
plant  has  reached  a  certain  stage  of  development  its 
growth  is  stopped,  and  for  a  more  or  less  lengthy 
period  it  remains  in  the  adult  stage,  in  what  seems  to  be 
equilibrium.  But  even  then  there  is  no  check  in  the 
manufacture  of  living  matter;  there  is  only  a  com- 
pensation between  its  production  and  its  destruction. 

It  is  important  to  reduce  to  order  the  ideas  on  this 
important  subject,  which  at  present  are  confused, 
inconsistent,  and  contradictory.  In  biology  grievous 
confusion  reigns. 

§  i.  EFFECT  OF  THE  VITAL  ACTIVITY. 
DESTRUCTION  OR  GROWTH? 

Distinction  between  the  Living  Substance  and  tJie 
Reserve-stuff  mingled  ivith  it. — The  physiology  of 
nutrition  has  given  rise  to  a  vast  body  of  research 
during  the  last  half-century.  Physiological  schools, 
masters  and  pupils,  such  as  the  school  at  Munich 
under  Voit  and  Pettenkofer,  Pfltiger's  at  Bonn, 
Rubner's,  and  those  of  Zuntz  and  von  Noorden  at 
Berlin,  and  a  large  number  of  zootechnical  and  agri- 
cultural laboratories  through  the  whole  world  have  for 


NUTRITION.  211 

years  past  been  engaged  in  analyzing  ingesta  and 
egesta,  in  drawing  up  schedules  of  nutrition,  in  order 
to  determine  the  course  of  decomposition  and  re- 
constitution  of  the  living  material. 

If  I  were  asked  what,  in  my  opinion,  is  the  most 
general  result  of  all  this  labour,  I  would  reply  that  it 
has  affirmed  and  corroborated  the  important  distinc- 
tion which  must  be  drawn  between  living  substance, 
properly  so  called,  and  reserve-stuff.  The  latter,  the 
reserve-stuff  of  albuminoids,  carbohydrates,  and  fats, 
are  so  intimately  intermingled  with  the  living  sub- 
stance that  they  are  in  most  cases  very  difficult  to 
distinguish  from  it 

Organic  Destruction. — A  second  point,  which  is 
placed  equally  beyond  doubt,  is  that  the  vital  func- 
tional activity  is  accompanied  by  a  destruction  of  the 
immediate  principles  of  the  organism,  in  the  direction 
of  their  simplification.  This  functional  destruction 
cannot  be  doubted  in  the  case  of  differentiated  organs 
in  which  the  functional  activity  is  evident,  inter- 
mittent, and  in  some  measure  distinct  from  the  other 
vital  phenomena  which  take  place  in  them.  For 
example,  in  the  case  of  contracting  muscles  the 
respiratory  carbonic  acid  and  urinary  carbon  are  the 
irrefutable  proofs  of  this  destruction :  weak  in  repose, 
abundant  during  activity,  and  in  proportion  to  it 
There  can  be  no  doubt  on  this  point  The  truth 
laid  down  by  Claude  Bernard  under  the  name  of 
the  law  of  functional  destruction  has  been  doubly 
consecrated  by  experiment  and  theory.  According 
to  the  energetic  theory,  in  fact,  mechanical  and 
thermal  energies  manifested  in  the  vital  functional 
activity  can  only  have  their  source  in  the  chemical 
energy  set  free  by  the  destruction  of  the  immediate 


212  LIFE   AND   DEATH. 

principles  of  the  organism,  reduced  to  a  lower  degree 
of  complexity. 

Destruction  of  Reserve-stuff. — But  now  the  disagree- 
ment begins.  What  are  these  decomposed,  destroyed 
principles  ?  Do  they  belong  to  the  cellular  reserve- 
stuff  or  to  the  living  matter  properly  so  called  ? 
There  is  no  doubt  that  most  of  them  belong  to  the 
reserve-stuff.  For  example,  this  is  especially  true  of 
glycogen,  which  is  consumed  in  muscular  contraction 
just  as  coal  is  consumed  in  the  furnace  of  the  loco- 
motive ;  and  glycogen  is  a  reserve-stuff  of  muscle. 
These  reserve-stuffs  destroyed  in  the  functional 
activity  can  be  built  up  again  only  during  repose. 

But  it  is  not  yet  certain  whether  the  living 
matter  itself,  the  active  protoplasm,  the  muscular 
protoplasm,  takes  part  in  this  destruction,  whether  it 
provides  it  with  elements.  Experiments  have  proved 
contradictory.  Experimenters  have  isolated  the  nitro- 
genous wastes  (urea)  after  muscular  labour,  and  they 
have  compared  them  with  the  wastes  of  the  period  of 
repose.  These  nitrogenous  wastes  bear  witness  to  the 
destruction  of  albuminoid  substances,  and  the  latter 
are  the  constituent  principles  of  living  matter.  If — 
under  conditions  of  sufficient  alimentation — the  mus- 
cular functional  activity  involves  more  nitrogenous 
waste,  i.e.,  a  greater  destruction  of  albuminoids,  it 
might  be  supposed  that  the  living  material  properly 
so  called  has  been  used  up  and  destroyed  for  its 
own  purposes.  (And  here  again  there  might  be  a 
reserve-stuff  of  albuminoids,  distinct  from  the  living 
protoplasm  itself,  and  more  or  less  incorporated 
with  it.) 

But  experiment  so  far  has  not  given  decisive  results. 
The  latest  experimental  researches,  such  as  those  of 


NUTRITION.  213 

I  go  Kaup,  of  Vienna,  which  date  from  1902,  tell  us  as 
uncertain  a  tale  as  their  predecessors.  The  increase 
in  the  destruction  of  albumen  has  not  been  constant ; 
the  conditions  of  the  observations  do  not  justify  our 
making  an  assertion  either  pro  or  con. 

Destruction  of  Living  Matter. — As  no  certain 
answer  is  supplied  by  experiment,  theory  intervenes 
and  gives  two  conflicting  answers.  The  majority  of 
physiologists  are  inclined  to  believe  in  the  destruction 
of  tJu  Ircing  substance  as  the  result  of  its  own  func- 
tional activity.  The  functional  activity  would  there- 
fore destroy  not  only  the  reserve-stuff,  but  also  the 
protoplasmic  material.  This  is  the  current  view. 
Only  this  opinion  is  strongly  challenged  by  the 
positive  teaching  of  science.  It  is  certain  that  this 
material,  in  the  muscle,  is  but  little  attacked,  if  it 
is  attacked  at  all  We  have  seen  above  that  the 
physiologists,  with  Pfliiger  and  Chauveau,  are  agreed 
on  this  point.  The  vital  functional  activity  in  par- 
ticular is  destructive  to  the  reserve-stuffs.  It  does 
not  destroy  them  much;  it  destroys  the  organic 
material  still  less.  Both  would  be  repaired  in  func- 
tional repose 

Growth  of  Living  Matter. — The  second  assertion  is 
diametrically  opposed  to  this.  Not  only,  says  Le 
Dantec,  is  the  muscle  not  destroyed  in  the  functional 
activity,  but  it  grows.  Contrary  to  universal  opinion, 
the  protoplasmic  material  increases  by  activity,  and  it 
is  destroyed  in  repose.  There  would  thus  be  a 
general  law — the  law  of  functional  assimilation.  "  A 
cell  of  brewers'  yeast  when  introduced  into  a  sugared 
must  makes  this  must  ferment,  and  at  the  same  time, 
so  far  from  destroying  it,  it  increases  it  Now,  the 
fermentation  of  the  must  is  exactly  the  same  as  the 


214  LIFE   AND   DEATH. 

functional  activity  of  the  yeast."  It  is,  says  the  same 
author,  a  mistake  to  believe  that  the  phenomena  of 
functional  activity,  of  vital  activity,  only  takes  place 
at  the  price  of  organic  destruction.  Here,  then,  are 
these  two  competing  views.  They  are  not  so  very  far 
apart  as  a  matter  of  fact,  since  the  question  at  issue  is 
one  of  deciding  between  a  slight  destruction  and  a 
slight  growth,  but  theoretically  they  are  strongly 
opposed.  Moreover,  they  are  arbitrary,  and  experi- 
ment has  not  decided  between  them. 


§  2.   THE   TWO   CATEGORIES  OF   VITAL   PHENOMENA. 

Foundation  of  tJie  Idea  of  Functional  Destruction, 
Claude  Bernard. — The  doctrine  of  functional  de- 
struction has  been  laid  down  with  remarkable  power 
by  Claude  Bernard.  But  the  terms  in  which  he  has 
expressed  it  in  a  measure  betray  the  thoughts  of  the 
great  physiologist,  or,  at  any  rate,  overstep  the 
immediate  fact  he  had  in  view.  "  The  phenomena 
of  destruction  are  very  obvious.  When  movement  is 
produced,  when  the  muscle  contracts,  when  volition 
and  sensibility  are  manifested,  when  thought  is 
exercised,  when  the  gland  secretes,  then  the  sub- 
stance of  the  muscles,  of  the  nerves,  of  the  brain,  oi 
the  glandular  tissue,  becomes  disorganized,  destroyed, 
and  consumed.  So  that  every  manifestation  of  a 
phenomenon  in  the  living  being  is  necessarily  con- 
nected with  an  organic  destruction."  To  Claude 
Bernard  organic  destruction  is  a  truth.  To  Le  Dantec 
it  is  an  error.  Which  is  right?  Clearly  Claude 
Bernard.  He  bases  his  conviction  on  the  analyses 
of  the  materials  excreted  in  the  process  of  physio- 


NUTRITION.  215 

logical  work.  The  excreta  bear  witness  to  a  certain 
organic  demolition.  Generalizing  this  teaching  of 
experiment  the  illustrious  biologist  divined  the 
fundamental  law  of  energetics  before  the  idea  of 
energetics  had  made  much  way  in  France.  Every 
act  which  expends  energy,  which  produces  heat  or 
motion,  any  manifestation  whatever  that  may  be 
looked  upon  as  an  energetic  transformation,  neces- 
sarily expends  energy,  and  that  energy  is  borrowed 
from  the  substance  of  the  organism.  These  sub- 
stances are  simplified,  broken  up,  and  destroyed. 
Now  the  functional  activity  of  the  muscle  produces 
heat  and  movement  in  warm-blooded  as  well  as  in 
cold-blooded  animals.  The  functional  activity  of 
the  glands  produces  heat,  as  has  been  shown  by  the 
celebrated  experiments  of  C.  Ludwig  on  the  salivary 
secretion,  and  as  is  also  shown  by  the  study  of  thermal 
topography  in  the  vertebrates.  The  functional  activity 
of  the  nerves  and  the  brain  produces  a  slight  quantity 
of  electricity  and  heat,  as  most  observers  have  agreed. 
The  functional  activity  of  the  electrical  and  of  the 
photic  apparatus  also  expends  energy.  Finally,  the 
eye  which  receives  the  photic  impression  destroys  the 
purple  matter  of  the  retina,  and  that  purple  matter, 
as  we  well  know,  is  recuperated  in  the  dark  during 
the  repose  of  the  organ.  Everything  that  is  expressed 
objectively,  everything  that  is  a  phenomenon  in  the 
living  being — with  the  exception  of  growth  and 
formation,  which  are  generally  slow  phenomena,  and 
of  which  we  can  only  get  an  idea  by  the  comparison 
of  successive  states — all  these  energetic  manifestations 
suppose  a  destruction  of  organic  matter,  a  chemical 
simplification,  the  source  of  the  energy  manifested 
And  that  is  why  material  destruction  does  not  merely 

ID 


2l6  LIFE    AND    DEATH. 

coincide  with  functional  activity,  but  is  its  measure 
and  expression. 

The  Two  Kinds  of  Phenomena  of  Vitality. — Another 
point  on  which  Claude  Bernard  is  right  and  his 
opponent  is  wrong  is  not  less  fundamental.  What 
are  we  to  understand  by  functional  phenomena  ? 
This  is  the  very  point  at  issue.  Now,  in  the  mind  of 
physiologists,  this  expression  has  a  perfectly  definite 
meaning.  It  is  not  so  with  Le  Dantec.  Physiologists 
who  have  studied  animals  rather  high  in  organization 
— in  which  the  differentiation  of  phenomena  enables 
us  to  grasp  the  fundamental  distinction — have  readily 
recognized  that  the  phenomena  of  living  beings  are 
divided  into  two  categories.  There  are  some  which 
are  intermittent,  alternative,  which  take  place,  or  grow 
stronger  at  certain  moments,  but  which  cannot  be 
continuous — they  are  the  functional  acts ;  there  are 
others  in  which  this  characteristic  of  explosives, 
energetic  expenditure  and  intermittence,  do  not 
appear — they  are,  in  general,  the  nutritive  acts.  The 
muscle  which  contracts  shows  functional  activity.  It 
has  an  activity  and  a  repose.  During  this  apparent 
repose  we  must  not  say  that  it  is  dead  ;  it  has  a  life, 
but  that  life  is  obscure  as  far  as  the  salient  fact  of 
functional  movement  is  concerned.  The  salivary 
gland  which  throws  up  waves  of  saliva  when  the  food 
is  introduced  and  masticated  in  the  mouth,  or  when 
the  chord  of  the  tympanum  is  at  work,  is  in  a  state  of 
functional  activity ;  this  is  the  salient  phenomenon. 
But  before,  though  nothing,  absolutely  nothing,  was 
flowing  through  the  glandular  canal,  yet  the  gland 
was  not  reduced  to  the  condition  of  a  dead  organ  :  it 
was  living  a  more  obscure,  a  less  evident  life.  The 
microscopical  researches  of  Kiihne,  Lea,  and  Langley, 


NUTRITION.  217 

now  universally  verified,  show  us  that  during  this 
time  of  apparent  repose  the  cells  were  loading  up 
their  granulations  and  getting  ready  the  materials  of 
secretion,  as  just  now  the  muscle  at  rest  was  accumu- 
lating glycogen  and  the  reserve-stuff  which  are  to  be 
expended  and  destroyed  in  contraction.  Similarly, 
with  regard  to  the  functional  activity  of  the  other 
glands,  of  the  brain,  etc.  Claude  Bernard  was,  there- 
fore, perfectly  right,  when  he  took  as  his  model  the 
chemists  who  distinguished  between  exothermic  and 
endothermic  reactions,  and  who  classed  the  pheno- 
mena of  life  into  two  great  divisions :  those  of 
functional  activity,  and  those  of  functional  repose. 

ist  TJie  phenomena  of  functional  activity  "are 
those  which  'leap  to  the  eyes,'  and  by  which  we 
are  inclined  to  characterize  life.  They  are  con- 
ditioned by  the  effects  of  wear  and  tear,  of  chemical 
simplication,  and  of  the  organic  destruction  which 
liberates  energy."  And  it  must  be  so,  because  these 
functional  manifestations  expend  energy.  These 
phenomena,  which  are  the  most  obvious,  are  also  the 
least  specific  phenomena  of  vitality.  They  form 
part  of  the  general  phenomenality. 

2nd.  The  plienomena  which  accompany  functional 
repose  correspond  to  the  building  up  of  the  reserve- 
stuff  destroyed  in  the  preceding  period,  to  the  organiz- 
ing synthesis.  The  latter  remains  "  internal,  silent, 
concealed  in  its  phenomenal  expression,  noiselessly 
gathering  together  the  materials  which  will  be  ex- 
pended. We  do  not  see  these  phenomena  of 
organization  directly.  The  histologist  and  the 
embryogenist  alone,  following  the  development  of 
the  element  or  of  the  living  being,  sees  the  changes 
and  the  phases  which  reveal  this  silent  effort.  Here 


2l8  LIFE   AND   DEATH. 

is  a  store  of  substance ;  there,  the  formation  of 
an  envelope  or  a  nucleus ;  there,  a  division  or 
multiplication,  a  renewal."  This  type  of  phenomena 
is  the  only  type  which  has  no  direct  analogues : 
it  is  peculiar,  special  to  the  living  being :  what 
is  really  vital  is  this  evolutive  synthesis.  Life  is 
creation. 

Criticism  of  Claude  Bernard. — All  this  is  perfectly 
true.  Thirty  years  of  the  most  intensive  scientific 
development  have  run  by  since  these  lines  were 
written,  and  have  not  essentially  changed  the  ideas 
therein  expressed.  His  work  in  its  broad  lines 
remains  intact  Does  that  imply,  however,  that 
everything  is  perfect  in  detail  and  expression,  and 
that  there  is  no  reason  for  making  it  more  precise  or 
for  giving  it  fresh  form  ?  No  doubt  this  is  not  so. 
Although  Claude  Bernard  contributed  to  establish 
the  essential  distinction  between  the  real  living 
protoplasm  and  the  materials  of  reserve-stuff  which 
it  contains,  he  has  not  drawn  a  sufficiently  clear 
distinction  between  what  belongs  to  each  of  the 
categories.  He  has  not  specified,  in  relation  to 
organic  destruction,  what  bearing  it  has  on  the 
organic  materials  of  reserve-stuff.  Sometimes  he  uses 
the  term  "  organic  destruction,"  which  is  correct,  and 
sometimes  "vital  destruction,"  which  is  of  doubtful 
import  Further,  he  employs  an  obscure  and 
paradoxical  formula  to  characterize  the  obvious  but 
nevertheless  not  specific  phenomena  of  organic 
destruction,  and  he  says  :  "life  is  death.".  /Xrtu/U'  - 

Current  Views. — Nowadays,  if  I  may  express  a 
personal  opinion  on  this  important  distinction  be- 
tween functional  activity  and  functional  repose,  I 
should  say  that  after  having  distinguished  between 


NUTRITION.  2ig 

the  two  categories  of  phenomena  we  must  try  to 
correlate  them.  We  must  try  to  discover,  for 
instance,  what  there  is  in  common  between  the 
muscle  in  repose  and  the  muscle  in  contraction,  and 
to  perceive  in  the  muscular  toitus  a  kind  of  bridge 
thrown  between  these  two  conditions.  The  functional 
activity  would  be  uninterrupted,  but  it  would  have  its 
degrees  of  activity.  The  muscular  ton  us  would  be 
the  permanent  condition  of  an  activity  which  is  cap- 
able only  of  being  considerably  raised  or  lowered. 
Similarly  for  the  glandular  functional  activity ;  the 
periods  of  charge  must  be  connected  with  the  periods 
of  discharge.  In  a  word,  following  the  constant  path 
of  the  human  mind  in  scientific  knowledge,  after 
having  drawn  the  distinctions  that  are  necessary  to 
our  understanding  of  things,  we  must  obliterate  them. 
After  having  dug  our  ditches  we  must  fill  them  up 
again.  After  having  analyzed  we  must  synthesize. 
The  distinction  between  the  phenomena  of  functional 
activity  and  the  phenomena  of  functional  repose  or 
purely  vegetative  and  nutritive  activity,  though  only 
valid  in  the  case  of  a  provisional  and  approximate 
truth,  none  the  less  throws  light  on  the  obscure 
regions  of  biology. 

The  succession  of  energy  and  repose,  of  sleep  and 
awakening,  is  a  universal  law,  or  at  least  a  very 
general  law,  connected  with  the  laws  of  energetics. 
The  heart,  the  lungs,  the  muscles,  the  glands,  the 
brain  obey  in  the  most  obvious  manner  this  obligation 
of  rhythmical  activity.  The  reason  is  clear.  It  is 
because  the  functional  activity  involves  what  is 
generally  a  sudden  expenditure  of  energy,  and  this 
has  to  be  replaced  by  what  is  generally  a  slow 
process  of  reparation.  Functional  activity  is  an 


220  LIFE   AND    DEATH. 

explosive  destruction  of  a  chemical  reserve  which  is 
built  up  again  more  or  less  slowly. 

Criticism  of  Le  D anted s  "  Ne^v  Theory  of  Life? — 
Let  us  now  examine  the  antithesis  of  Claude 
Bernard's  views.  There  are  evidently  rudimentary 
organisms  in  which  the  differentiation  of  the  two 
categories  of  phenomena  is  but  little  marked ;  in 
which,  apart  from  the  movement,  it  is  impossible  to 
recognize  intermittent,  functional  activities  clearly 
distinct  from  morphogenic  activity.  It  is  not  in  this 
domain  of  the  indistinct  that  \ve  must  seek  the 
touchstone  of  physiological  distinctions.  Clearly,  we 
must  not  choose  these  elementary  plastids  to  test 
the  doctrine  of  functional  assimilation  and  functional 
destruction.  But  is  not  this  exactly  what  Le  Dantec 
did  when  he  began  his  researches  on  brewers'  yeast? 
When  we  try  to  examine  things,  we  must  choose  the 
conditions  under  which  they  are  differentiated,  and 
not  those  in  which  they  are  confused.  And  this  is 
why,  in  the  significant  words  of  Auguste  Comte,  "  the 
more  complex  living  beings  are,  the  better  known 
they  are  to  us."  The  philosopher  goes  still  farther 
in  this  direction,  and  adds  "directly  it  is  a  question 
of  the  characteristics  of  animality  we  must  start  from 
the  man,  and  see  how  those  characteristics  are  little 
by  little  degraded,  rather  than  start  from  the  sponge 
and  endeavour  to  discover  how  these  characteristics 
are  developed.  The  animal  life  of  the  man  assists 
us  to  understand  the  life  of  the  sponge,  but  the 
converse  is  not  true." 

When,  moreover,  we  consider  a  vegetable  organism 
such  as  yeast,  which  derives  its  energy,  not  from 
itself,  not  from  the  potential  chemical  energy  of  its 
reserve- stuff,  but  directly  from  the  medium — that  is 


NUTRITION.  221 

to  say,  from  the  potential  chemical  energy  of  the 
compounds  which  form  its  medium  of  culture, — we 
then  find  ourselves  in  the  worst  possible  situation  for 
the  recognition  of  organic  destruction.  Further,  it  is 
doubly  wrong  to  assert  that  in  so  ill-chosen  a  type 
the  functional  phenomena  do  not  result  from  an 
organic  destruction — for  at  first  there  are  no  very 
distinct  functional  phenomena  here — and,  in  the  second 
place,  there  certainly  is  organic  destruction.  The 
phenomena  of  the  morphogenic  vitality  detected  in 
the  yeast  are  the  exact  concomitants,  or  the  results, 
of  the  destruction  of  an  organic  compound,  which  in 
this  case  is  sugar.  The  yeast  destroys  an  immediate 
principle,  and  this  is  the  point  of  departure  of  its  vital 
manifestations ;  only,  it  has  not,  as  a  preliminary, 
clearly  incorporated  and  assimilated  this  principle. 
When,  therefore,  the  functional  phenomena  are 
effaced  and  disappear,  we  none  the  less  find  pheno- 
mena of  destruction  of  organic  compounds  which  are 
in  a  measure,  a  preface  to  the  phenomena  of  growth. 
This  is  what  happens  in  the  case  of  brewers'  yeast : 
and  here,  again,  the  two  categories  of  facts  exist 
Once  more,  we  find,  in  the  first  place,  the  phenomena 
of  destruction  (destruction  of  sugar,  reduced  by 
simplification  to  alcohol  and  carbonic  acid) — pheno- 
mena which  this  time  no  longer  respond  to  obvious 
functional  manifestations ;  and,  in  the  second  place, 
the  phenomena  of  chemical  and  organogenic  synthesis, 
corresponding  to  the  growth  of  the  yeast  and  the 
multiplication  of  its  protoplasm.  The  former  are  no 
longer  detected,  as  we  have  just  said,  by  striking 
manifestations.  However,  it  is  not  true  that  every- 
thing which  is  visible  and  which  may  be  isolated 
outside  the  activity  of  the  yeast  is  part  of  those 


222  LIFE   AND   DEATH. 

phenomena.  The  boiling  of  the  juice  or  the  mash, 
the  heat  given  off  by  the  copper,  all  this  phenomenal 
apparatus  is  but  the  consequence  of  the  production  of 
the  carbonic  acid  and  of  its  liberations — i.e.,  the 
consequence  of  the  act  of  destruction  of  the  sugar. 
Here  is  organic  destruction  with  its  energetic 
manifestations ! 

This  example  of  the  life  of  brewers'  yeast,  of  the 
saccharomyces,  specially  chosen  by  Le  Dantec  as 
being  absolutely  clear  and  giving  the  best  illustration 
of  his  argument,  contradicts  him  at  every  point.  The 
general  thesis  of  this  vigorous  thinker  is  that  we 
cannot  distinguish  between  the  two  parts  of  the  vital 
act,  organic  destruction,  and  assimilating  synthesis  ; 
that  these  two  acts  are  not  successive  ;  that  they  give 
rise  to  phenomenal  manifestations  equally  evident, 
apparent,  or  striking.  Now,  in  the  case  of  yeast,  the 
phenomenon  of  destruction  is  clearly  distinct  from 
that  of  the  assimilating  synthesis  which  multiplies 
the  substance  of  the  saccharomyces.  In  fact,  the 
action  is  realized  by  means  of  an  alcoholic  diastase 
manufactured  by  the  cell ;  and  Biichner  succeeded  in 
isolating  this  alcoholic  ferment  which  splits  up  the 
sugar  into  alcohol  and  carbonic  acid,  and  also  in  vitro 
and  in  vivo,  makes  the  vat  boil  and  heats  the  liquid. 
All  the  yeast  is  at  work  at  once,  says  M.  Dantec. 
No,  and  this  is  the  proof. 

And,  further,  Pasteur  himself,  who  had  shown  the 
relation  of  the  decomposition  of  the  sugar  to  the  fact 
of  the  growth  of  the  yeast  and  of  the  production 
of  accessory  substances  such  as  succinic  acid  and 
glycerine,  always  referred  to  correlation  between  these 
phenomena.  The  destruction  of  the  sugar  is  the 
correlative  of  the  life  of  the  yeast.  This  was  his 


NUTRITION.  223 

favourite  formula.  It  never  entered  his  head  that 
there  could  be  a  confusion  instead  of  a  correlation, 
and  that  there  might  be  only  one  and  the  same  act, 
the  phases  of  which  would  be  indistinguishable. 
This  unfortunate  idea,  which  was  fated  to  be  so 
rapidly  contradicted,  is  due  to  Le  Dantec.  Far 
from  it  being  the  case,  Pasteur  had  distinguished 
the  ferment  function  from  the  life  of  the  yeast 
According  to  him,  the  yeast  may  exist  sometimes  as 
a  ferment  and  sometimes  otherwise. 


§  3.  CORRELATION  OF  Two  ORDERS  OF 
VITAL  FACTS. 

It  is  this  correlation  between  acts  distinct  in  them- 
selves but  usually  connected  that  was  announced  by 
Claude  Bernard.  And,  mitabile  dictu — and  this  is  the 
natural  outcome  of  the  perfect  sanity  of  mind  of  this 
great  physiologist — it  happens  that  not  only  Pasteur's 
researches,  but  the  development  of  a  new  science, 
Energetics,  and  Btichner's  discovery  lend  support  to 
his  views,  and  that,  too,  in  a  field  where  one  would 
have  thought  they  had  no  application.  Le  Dantec  is 
wrong  when  he  declares  that  these  ideas  only  apply  to 
vertebrates.  ''It  is  clear,"  he  says  on  several  occa- 
sions, "  that  the  author  has  in  view  the  metazoa  and 
even  the  vertebrates."  Well .'  no.  All  that  is  general, 
universally  applicable,  and  universally  true.  So  that 
there  are  two  orders  of  distinct  phenomena  ener- 
getically opposed  and  certainly  connected.  \Ve  need 
only  repeat  Claude  Bernard's  own  words  quoted  by 
Le  Dantec  in  order  to  confute  them. 

Law  of  Connection  of  Two  Orders  of  Vital  Facts. 
— "These  phenomena  [of  organic  destruction  and  of 


224  LIFE    AND    DEATH. 

assimilating  synthesis]  are  simultaneously  produced 
in  every  living  being,  in  a  connection  which  cannot 
be  broken.  The  disorganization  or  dissimilation  uses 
up  living  matter  [by  this  we  must  understand  the 
reserve-stuff,  as  will  be  seen  later  on  in  the  quotation] 
in  the  organs  in  function:  the  assimilating  synthesis 
regenerates  the  tissues;  it  gathers  together  the  re- 
serve-stuff which  the  vital  activity  must  expend. 
These  two  operations  of  destruction  and  renovation, 
inverse  the  one  to  the  other,  are  absolutely  connected 
and  inseparable,  in  this  sense  at  any  rate,  that  de- 
struction is  the  necessary  condition  of  renovation. 
The  phenomena  of  functional  destruction  are  them- 
selves the  precursors  and  the  instigators  of  material 
regeneration,  of  the  formative  process  which  is  silently 
going  on  in  the  intimacy  of  the  tissues.  The  losses 
are  repaired  as  they  take  place;  and  equilibrium  being 
re-established  as  soon  as  it  tends  to  be  broken,  the 
body  is  maintained  in  its  composition." 

It  is  perfectly  right  and  wise  to  say  with  Claude 
Bernard  that  the  two  orders  of  facts  are  successive, 
and  that  one  is  normally  the  inciting  condition  of  the 
other.  The  possibility  of  the  development  of  the 
yeast  when  fermentation  fails,  and  the  weakness  of 
this  development  on  the  other  hand  under  these  con- 
ditions, are  an  excellent  proof  of  this.  The  one  proves 
the  essential  independence  of  the  two  orders  of  facts, 
the  other  the  inciting  and  provoking  virtue  of  the  first 
relatively  to  the  second.  The  experimental  truth  is 
thus  expressed  with  a  minimum  of  uncertainty.  We 
know  the  facts  which  led  Le  Dantec  to  formulate  his 
law  of  functional  assimilation — namely,  that  the 
functional  activity  is  useful  or  indispensable  to  the 
growth  of  the  organ ;  that  the  organs  which  are 


NUTRITION.  225 

functionally  active  grow,  and  those  which  do  not  act 
become  atrophied.  We  are  only  expressing  the  facts 
when  we  say  that  the  organic  destructions  that  go  on  in 
the  living  being  (whether  at  the  expense  of  its  reserve- 
stuff  or  at  the  expense  of  its  medium,  or  whether  it  be 
even  slightly  at  the  expense  of  the  plastic  substance 
itself)  are  the  antecedent,  the  inciting  agent  or  the 
normal  condition  of  the  chemical  and  organogenic 
syntheses  which  create  the  new  protoplasm. 

On  the  other  hand,  we  are  wrong  if  we  hold  with 
Le  Dantec  that  instead  of  two  chemical  operations 
there  is  only  one,  that  which  creates  the  new  proto- 
plasm. The  obvious  destruction  is  neglected ;  it  is 
deliberately  passed  over.  He  does  not  see  that  it  is 
necessary  to  liberate  the  energy  employed  in  the 
construction,  by  complication,  of  this  highly  complex 
substance  which  is  the  new  protoplasm.  He  really 
seems  to  have  made  up  his  mind  not  to  analyze  the 
phenomenon.  If  we  decline  to  admit  that  to  the  first 
act  of  functional  destruction  succeeds  a  second, 
assimilation  or  organogenic  synthesis,  we  are  look- 
ing at  elementary  beings,  in  which  the  succession 
cannot  be  grasped,  as  we  look  on  brewers'  yeast 
We  not  only  mean  that  the  morphogenic  assimilation 
results  from  the  functional  activity ;  we  mean  that  it 
results  from  it  directly,  immediately,  that  it  is  the 
functional  activity  itself.  Experiment  tells  us  nothing 
of  all  this  It  shows  us  the  real  facts,  the  facts  of  the 
destruction  of  an  organic  immediate  principle,  the 
sugar,  and  the  fact  that  an  assimilating  synthesis  is 
the  correlative  of  this  destruction.  Besides,  if  it  is 
impossible  in  examples  of  this  kind  to  exhibit  the 
succession,  it  is  perfectly  easy  in  beings  of  a  higher 
order.  It  is,  then,  clearly  seen  that  the  preliminary 


226  LIFE   AND    DEATH. 

destruction  of  a  reserve-stuff  (and  perhaps  of  a  small 
quantity  of  the  living  substance)  precedes  and  con- 
ditions the  formation  of  a  greater  quantity  of  this 
living  matter — in  other  words,  the  growth  of  the 
protoplasm  of  the  organ. 

Contradictions  in  the  New  Theoty. — Moreover,  these 
mistakes  involve  those  who  make  them  in  a  series  of 
inextricable  contradictions.  Here,  for  example,  is 
life;  it  is  found,  they  say,  in  three  forms: — Life 
manifested,  or  condition  1°;  latent  life,  or  condition 
3°.  So  far  this  is  the  classical  theory;  but  they  add 
a  condition  2°,  which  is  what  might  be  called  patJio- 
logical  or  incomplete  life.  This  is  defined  by  the 
following  characteristic: — That  its  functional  pheno- 
mena are  identical  with  those  in  the  first  form,  but 
that  they  are  not  accompanied  by  assimilation  and  by 
protoplasmic  growth.  But  since,  they  say,  growth  is 
the  chemical  consequence  of  the  functional  activity, 
since  it  is  so  to  speak  its  metabolic  aspect,  since  it  is 
confused  writh  it,  and  inseparable  from  it,  by  the 
argument — then  it  is  contradictory  and  logically 
absurd  to  speak  of  condition  2°.  It  would  be  ac- 
knowledging in  the  case  of  the  anucleated  merozoite, 
for  example,  a  functional  activity  unaccompanied  by 
assimilation,  yet  identical  with  the  functional  activity 
which  is  accompanied  by  assimilation  in  the  nucleated 
merozoite.  The  general  movement,  that  of  the  cilia, 
the  taking  of  food,  the  evacuation  of  the  faeces,  the 
contraction  of  the  pulsatile  vacuoles,  are  the  same. 
And  this  fact  is  the  best  proof  that  this  vital  func- 
tional activity  (with  the  organic  destruction  which  is 
its  energetic  source)  must  be  distinguished  from  the 
assimilation  which  usually  follows  it,  and  which  in 
exceptional  cases  may  not  follow  it. 


NUTRITION.  227 

We  shall  carry  this  discussion  no  farther.  We  have 
examined  at  some  length  Le  Dantec's  views,  and  we 
have  contrasted  them  with  the  doctrine  which  has 
been  current  in  general  physiology  since  the  time  of 
Claude  Bernard,  and  this  comparison  does  not  turn 
out  quite  to  their  advantage.  It  was  inevitable  that 
the  experimental  and  realistic  spirit  which  inspired 
the  doctrine  of  the  celebrated  physiologist  made  his 
work  really  too  systematic.  His  formula,  "life  is 
death,"  and  the  form  he  gave  his  ideas,  are  not  always 
irreproachably  correct.  They  lend  themselves  at 
times  to  criticism.  Sometimes  they  require  commen- 
tary. These  are  errors  of  detail  which  Le  Dantec 
has  summarized  somewhat  roughly.  There  is  no 
necessity  to  do  this  in  his  own  case.  We  pay  our 
tribute  to  the  clearness  of  his  language,  although  \ve 
believe  the  foundations  of  his  system  are  false  and 
ill-founded.  Their  rigour  is  purely  verbal.  Their 
external  qualities,  their  careful  arrangement  are  well 
adapted  to  the  seduction  of  the  systematic  mind 
prepared  by  mathematical  teaching.  This  new  theory 
of  life  is  presented  with  pedagogic  talent  of  the 
highest  order.  We  think  we  have  shown  that  the 
foundations  are  entirely  fallacious,  in  particular  the 
following: — Vital  condition  Xo.  23;  the  confusion  be- 
tween functional  activity  and  assimilating  synthesis ; 
the  so-called  absolute  connection  between  morpho- 
geny  and  chemical  composition  ;  the  fundamental 
distinction  between  elementary  life  and  individual  life. 

§  4.  CHARACTERISTICS  OF  NUTRITION. 

Definition  of  Nutrition. — As  we  have  just  seen,  the 
organism  is  the  scene  of  chemical  reactions  of  two 


228  LIFE   AND   DEATH. 

kinds,  the  one  destructive  and  simplifying,  the  other 
synthetic,  constructive,  or  assimilating.  This  totality 
of  reactions  constitutes  nutrition.  Hence  the  two 
phases  that  it  is  convenient  to  consider  in  this  func- 
tion— assimilation  and  disassimilation.  This  twofold 
chemical  movement  or  metabolism  corresponding  to 
the  two  categories  of  vital  phenomena,  of  destruction 
(catabolism)  and  of  synthesis  (anabolism)  is  therefore 
the  chemical  sign  of  vitality  in  all  its  forms.  But  it 
is  clear  that  disassimilation  or  organic  destruction, 
which  is  destined  to  furnish  energy  to  the  organism 
for  its  different  operations,  reappears  in  the  plan  of 
the  general  phenomena  of  nature.  It  is  not  specific- 
ally vital  in  its  principle.  Assimilation,  on  the  other 
hand,  is  in  this  respect  much  more  characteristic. 

To  some  physiologists  nutrition  is  only  assimila- 
tion. Of  the  two  aspects  of  metabolism  they  consider 
only  one,  the  most  typical,  Ad-similare,  to  assimilate, 
to  restore  the  substance  borrowed  from  the  ambient 
medium,  the  alimentary  substances,  similar  to  living 
matter,  to  make  living  matter  of  them,  to  increase 
active  protoplasm — this  is  indeed  the  most  striking 
phenomenon  of  vitality.  To  grow,  to  increase,  to 
expand,  to  invade,  is  the  law  of  living  matter. 
Assimilation,  nutrition  in  its  essentials,  is,  according 
to  the  definition  of  Ch.  Robin,  "the  production  by  the 
living  being  of  a  substance  identical  with  its  own." 
It  is  the  act  by  which  the  living  matter,  the  proto- 
plasm of  a  given  being,  is  created. 

Permanence  in  Nutrition. — Nutrition  presents  one 
quite  remarkable  character — permanence.  It  is  a  vital 
manifestation,  a  property  if  we  look  at  it  in  the  cell, 
in  the  living  substance,  a  function  if  we  consider  it  in 
the  animal  or  in  the  plant  as  a  whole,  which  is  never 


NUTRITION.  229 

arrested  Its  suspension  involves  ipso  facto  ihe  sus- 
pension of  life  itself.  It  is,  in  the  words  of  Claude 
Bernard,  that  property  of  nutrition  "  which,  as  long  as 
it  exists  in  an  element,  compels  us  to  believe  that  this 
element  is  alive,  and  which,  when  it  is  absent,  compels 
us  to  believe  that  it  is  dead.  It  dominates  all  others 
by  its  generality  and  its  importance.  In  a  word,  it  is 
the  absolute  test  of  vitality." 

Biological  Energetics  shows  the  Importance  of 
Nutrition* — We  have  indicated  in  advance  the  reason 
of  its  importance,  showing  that  its  two  phases,  dis- 
assimilation  and  assimilation,  are  the  energetic 
condition  of  the  two  kinds  of  vital  phenomena 
which  we  can  distinguish. 

Nutrition  is  a  manufacture  of  protoplasm  at  the 
expense  of  the  materials  of  the  cellular  ambient 
medium,  which  are  assimilated — />.,  made  chemically 
and  physically  similar  to  living  matter  and  to  the 
reserves  it  stores  up.  This  operation,  which  is 
peculiarly  chemical,  is  therefore  indicated  by  the 
borrowing  of  materials  from  the  external  world,  a 
borrowing  which  is  always  going  on.  because  the 
operation  is  permanent,  and,  let  me  add,  because  of 
the  continual  rejection  of  the  waste  products  of 
this  manufacture.  Our  formula  is : — Nutrition  is  a 
chemistry  which  persists. 

The  Idea  of  the  Vital  Vortex  is  Erroneous. —  Here 
the  effect  has  hidden  the  cause  from  the  eyes 
of  the  biologists.  They  have  been  struck  by  the 
incessant  entry  and  exit,  by  the  never-ceasing  passage, 
by  the  cycle  of  matter  through  the  living  being 
without  guessing  its  why  and  wherefore ;  and  they 
have  taken  as  a  picture  of  the  living  being  a  vortex 
in  which  the  essential  form  is  maintained  while  the 


230  LIFE    AND    DEATH. 

matter,  which  is  accessory,  flows  on  without  a  check. 
This  is  Cuvier's  vital  vortex.  But  for  what  purpose 
is  this  circulating  matter  used  ?  They  thought  that 
it  was  employed  entirely  for  the  reconstitution  of 
the  living  substance,  continually  and  inevitably  de- 
stroyed by  the  vital  Minotaur. 

Destruction  of  Reserve- stuff. — Here  again  there  is 
a  mistake.  Really  living  substance  is  but  little 
destroyed,  and  consequently  requires  very  little 
renewal  by  the  functional  activity  of  the  animal 
machine.  Its  metabolism — destruction  and  renewal 
— is  in  every  case  infinitely  less  than  is  supposed  in 
the  classical  image  of  the  vital  vortex.  It  is  the 
merit  of  physiologists,  and  particularly  of  Pfliiger  and 
Chauveau,  to  have  worked  for  nearly  forty  years 
to  establish  this  truth.  They  have  proved  it,  at 
least  as  far  as  the  muscular  tissue  is  concerned. 
Protoplasm,  properly  so-called,  is  only  destroyed 
as  the  organs  of  a  steam  engine  are  destroyed — its 
tubes,  its  boiler,  its  furnace.  And  it  matters  little. 
We  know  that  such  an  engine  uses  much  coal,  and  we 
know  very  little  of  its  machinery  and  its  metallic 
frame.  And  so  it  is  with  the  cell,  the  living  machine. 
A  very  small  portion  of  the  food  introduced  will  be 
assimilated  in  the  living  substance.  By  far  the 
greater  part  of  it  is  destined  to  be  worked  up  by  the 
protoplasm  and  placed  in  reserve  under  the  form  of 
glycogen,  albumen,  and  fat,  etc.  —  i.e.,  compounds 
which  are  not  the  really  living  substance,  the  hereditary 
protoplasm,  but  the  products  of  its  industry,  just  as 
they  are  or  may  be  the  products  of  the  industry  of 
the  chemist  working  in  his  laboratory.  They  will  be 
expended  for  the  purpose  of  furnishing  the  necessary 
energy  to  the  vital  functional  activity,  muscular 


NUTRITION.  231 

contraction,  secretion,  heat,  etc.,  just  as  coal  is 
expended  to  set  the  steam  engine  going.  The  proof 
as  far  as  the  muscle  is  concerned  does  not  stand 
alone.  There  are  other  examples.  In  particular, 
micrographic  physiologists  who  have  studied  nervous 
phenomena  say  that  the  anatomical  elements  of  the 
brain  last  indefinitely,  and  that  they  continue  as  they 
are,  without  renewal  from  birth  to  death.  The 
permanence  of  the  consciousness,  be  it  said  in 
passing,  is  connected  by  them  with  the  permanence 
of  the  cerebral  element  (Marinesco). 

Thus  destruction  is  very  restricted.  There  is  only 
a  very  slight  disassimilation  of  the  living  matter, 
properly  so-called,  in  the  course  of  the  vital  functional 
activity.  We  may  even  go  farther  than  this  ex- 
perimental fact.  This  is  what  Le  Dantec  has  done 
when  he  claims  that  there  is  even  an  assimilation,  an 
increase  of  the  protoplasm.  Strictly  speaking,  this 
is  possible,  but  there  is  no  certain  proof  of  it ;  and  in 
any  case  we  cannot  agree  with  him  when  he  affirms 
that  the  increase  is  the  direct  result  of  the  functional 
activity  and  blends  with  it  in  one  single,  unique 
operation.  We  must,  on  the  contrary,  agree  with 
Claude  Bernard  that  it  is  only  a  consequence  of  it, 
that  it  is  produced  in  consequence  of  the  existence  of 
a  bond  of  correlation  between  organic  destruction  and 
assimilating  synthesis. 

Why  is  there  this  bond  ?  That  is  easily  under- 
stood if  we  reflect  that  the  assimilating  synthesis,  an 
operation  of  endothermic,  chemical  complexity,  natur- 
ally requires  an  exothermic  counterpart,  the  organic 
destruction  which  will  set  free  this  necessary  energy. 

Formative  Assimilation  of  Reserve^stuff.  Forma' 
ting  Assimilation  of  Protoplasm.— It  follows  that 

16 


232  LIFE   AND   DEATH. 

there  are  in  nutritive  assimilation  itself  two  distinct 
acts.  The  one  consisting  of  the  manufacture  of 
reserve-stuff  is  the  more  obvious  but  the  less 
specific ;  the  other,  really  essential,  is  assimilation 
properly  so-called,  the  reconstitution  of  the  proto- 
plasm. The  former  is  indispensable  to  the  pro- 
duction of  the  most  prominent  acts  of  vitality — 
movement,  secretion,  production  of  heat.  If  it  is 
suspended,  functional  activity  is  arrested.  We  get 
apparent  death,  or  latent  life.  But  if  the  real  assimi- 
lation is  arrested,  we  have  real  deatJi. 

According  to  this  there  would  be  a  fundamental 
distinction  between  real  and  apparent  death.  The 
former  would  be  characterized  by  an  arrest  of  the 
protoplasmic  assimilation  which  is  externally  indicated 
by  no  sign.  On  the  other  hand,  apparent  death 
would  be  characterized  by  the  arrest  of  the  formation 
and  destruction  of  reserve-stuff.  It  would  be  ex- 
ternally manifested  by  two  signs  : — The  suppression 
of  material  exchanges  with  the  medium  (respiration, 
alimentation)  and  the  suppression  of  the  functional 
acts  (production  of  movement,  of  heat,  of  electricity, 
of  glandular  excretion). 

Such  would  be  the  most  expedient  test  for  apparent 
or  real  death.  The  question  occurs  in  the  case  of 
grains  of  corn  in  Egyptian  tombs,  and  also  of 
hibernating  animals  and  reviviscent  beings,  and,  in 
general,  in  the  case  of  what  has  been  called  the  state 
of  latent  life.  But  from  the  practical  point  of  view 
it  is  extremely  difficult  to  apply  this  test  and  to 
decide  if  the  phenomena  which  are  arrested  in  the 
grain  at  maturity,  in  Lceuwenhoek's  tardigrada,1 

1  Bear-animalcules,  Sloth-animalcules.  An  order  of  Arach- 
nida.— TR. 


NUTRITION.  233 

and  in  the  dried-up  Anguillulidae1  of  Baker  and 
Spallanzani,  in  the  encysted  colpoda2  that  a  drop  of 
warm  water  will  revive,  in  the  animals  exposed  by 
E.  Yung  and  Pictet  to  a  cold  of  more  than  a 
100°  C.  below  zero,  are  due  to  the  general  arrest  of 
the  two  forms  of  assimilation,  or  to  the  arrest  of  the 
manufacture  and  utilization  of  reserve-stuff  alone,  or 
finally,  to  the  arrest  of  protoplasmic  assimilation 
alone.  The  latter,  which  is  already  very  restricted 
in  beings  in  a  normal  condition  whose  growth  is 
terminated,  may  fall  to  the  lowest  degree  in  the 
being  which,  having  no  functional  activity,  is  assimi- 
lating nothing.  So  that,  to  cut  the  question  short, 
the  experimenter  who  measures  the  value  of  the 
exchanges  between  the  being  and  the  medium  has 
seldom  to  do  more  than  decide  between  little  and 
nothing.  Hence  his  perplexity.  But  if  experiment 
hesitates,  theory  affirms :  it  admits  a  priori  that  the 
movement  of  protoplasmic  assimilation,  an  essential 
sign  of  vitality,  is  neither  checked  nor  renewed,  but 
proceeds  continuously. 

Is  Nutrition,  tlie  Assimilating  Synthesis,  inter- 
rupted?— Nevertheless,  there  are  many  reasons  for 
suspending  all  judgment  as  to  this  interpretation. 
It  is  questioned  by  most  biologists.  According  to 
A.  Gautier,  the  preserved  grain  of  corn  and  the  dried 
up  rotifera  are  not  really  alive  ;  they  are  like  clocks 
in  working  order,  ready  to  tell  the  time,  but  awaiting 
in  absolute  repose  the  first  vibration  which  will  set 
them  going.  As  for  the  grain,  it  is  the  air,  heat,  and 

1  Minute  thread  worms,  known  as  paste-eels  and  vinegar* 
eels.— TR. 

2  Genus  of  Infusoria.     ColpoiUa  cucullus  is  found  in  infusions 
of  hay— TR. 


234  LIFE   AND   DEATH. 

moisture  which  supply  the  first  impulse.  In  other 
words,  the  organization  proper  to  the  manifestation  of 
life  remains,  but  there  is  no  life.  The  so-called 
arrested  life  is  not  a  life. 

It  must  be  said,  however,  that  the  majority  of 
physiologists  refuse  to  accept  this  interpretation. 
They  believe  in  an  attenuation  of  the  nutritive 
synthesis  and  not  in  its  complete  destruction.  They 
think  that  this  total  suppression  would  be  contrary 
to  current  ideas  relative  to  the  perpetuity  of  the 
protoplasm  and  the  limited  duration  of  the  living 
element.  The  natural  medium  is  variable,  and  even 
the  mineral  cannot  remain  eternally  fixed.  Still  less 
is  perennity  a  property  of  the  living  being.  If 
ordinary  life  is  for  each  individual  of  limited  duration, 
the  arrested  life  must  also  be  of  limited  duration. 
We  cannot  believe  that  after  an  indefinitely  prolonged 
sleep  the  grain  of  corn,  or  the  paste-eel,  or  the 
colpoda,  emerging  from  their  torpor  can  resume  their 
existence,  like  the  Sleeping  Beauty,  at  the  point  at 
which  it  was  interrupted,  and  thus  pass  with  a  bound, 
as  it  were,  through  the  centuries. 

In  fact  the  maintenance  of  the  vitality  of  grains 
of  corn  from  the  Egyptian  tombs  and  their  aptitude 
to  germinate  after  thousands  of  years  are  only  fables 
or  the  result  of  imposture.  Maspero,  in  a  letter 
addressed  to  M.  E.  Griffon  on  the  isth  July  1901, 
has  clearly  summed  up  the  situation  by  saying  that 
the  grains  of  corn  bought  from  the  fellahs  almost 
always  germinate,  but  that  this  is  never  the  case  with 
those  that  the  experimenter  himself  takes  from  the 
tombs. 

To  sum  up,  we  must  use  the  same  language  of 
nutrition  and  of  life,  of  their  uninterrupted  progress, 


NUTRITION.  235 

of  their  continuity,  of  their  permanence,  of  their 
activity,  and  of  their  slackening.  Living  matter  is 
always  growing,  much  or  little,  slowly  or  quickly, 
in  its  reserve-stuff  or  in  its  protoplasm,  for  expenditure 
or  accumulation.  This  inevitability  of  growth  defines 
it,  characterizes  it,  and  sums  up  its  activity.  Develop- 
ment and  the  evolution  of  growth  are  consequences  or 
aspects  of  nutrition. 


BOOK  IV. 

THE   LIFE   OF   MATTER. 

Summary:  Chap.  I.  Universal  life — Opinions  of  philosophers 
and  poets — Continuity  between  brute  and  living  bodies — 
Origin  of  this  principle. — Chap.  II.  Origin  of  brute  matter 
in  living  matter. — Chap.  III.  Organization  and  chemical 
composition  of  brute  and  living  bodies. — Chap.  IV.  Evolu- 
tion and  transformation  of  brute  and  living  bodies. — 
Chap.  V.  Possession  of  a  specific  form — Living  bodies  and 
crystals — Cicatrization. — Chap.  VI.  Nutrition  in  the  living 
body  and  in  the  crystal. — Chap.  VII.  Generation  in  brute 
and  in  living  bodies — Spontaneous  generation. 

Apparent  Differences  between  Living  and  Brute 
Bodies.  The  Two  Kingdoms. — It  seems  at  first 
impossible  that  there  should  be  any  essential 
similarity  between  an  inanimate  object  and  a  living 
being.  What  resemblance  can  be  discovered  between 
a  stone,  a  lion,  and  an  oak  ?  A  comparison  of  the 
inert  and  immovable  pebble  with  the  leaping  animal, 
and  with  the  plant  extending  its  foliage  gives  an 
impression  of  vivid  contrast.  Between  the  organic 
and  the  inorganic  worlds  there  seems  to  be  an  abyss. 
The  first  impressions  we  receive  confirm  this  view ; 
superficial  investigation  furnishes  arguments  for  it. 
There  is  thus  aroused  in  the  mind  of  the  child,  and 
later  in  that  of  the  man,  a  sharply  marked  distinction 
between  the  natural  objects  of  the  mineral  kingdom 
on  the  one  hand,  and  those  of  the  two  kingdoms  of 
living  beings  on  the  other. 

236 


THE  LIFE  OF  MATTER.  237 

But  a  more  Intimate  knowledge  daily  tends  to 
throw  doubt  upon  the  rigour  or  the  absolute  character 
of  such  a  distinction.  It  shows  that  brute  matter  can 
no  longer  be  placed  on  one  side  and  living  beings  on 
the  other.  Scientists  deliberately  speak  of  athe  life 
of  matter,7"  which  seems  to  the  average  man  a  con- 
tradiction in  terms.  They  discover  in  certain  classes 
of  mineral  bodies  almost  all  the  attributes  of  life. 
They  find  in  others  fainter,  but  still  recognizable 
indications  of  an  undeniable  relationship. 

We 'propose  to  pass  in  review  these  analogies  and 
rpgpiTflilaiinre  as  has  already  been  done  in  a  fairly 
complete  manner  by  Leo  Errera,  C  EL  Gnillanme, 
C  Bourdean,  Ed.  Griffon,  and  others.  We  will  con- 
sider the  fine  researches  of  Ranber,  of  Ostwald, 
and  of  Tammann  upon  crystals  and  crystalline  germs 
— researches  which  are  merely  a  continuation  of  those 
of  Pasteur  and  of  Gernez.  These  show  that  crystaH- 
Hne  bodies  are  endowed  with  the  principal  attributes 
of  living  beings — *>,  a  rigorously  defined  form ;  an 
aptitude  for  acquiring  it,  and  for  re-establishing  it  by 
rrpaifing  any  mutilations  that  may  be  inflicted  upon 
it;  nutritive  growth  at  the  expense  of  the  mother 
liquor  which  constitutes  its  culture  medium ;  and, 
finally — a  still  more  incredible  property — all  the 
characteristics  of  reproduction  by  generation.  Other 
curious  facts  observed  by  skilful  physicists — W. 
Roberts-Austen,  W.  Spring,  Stead,  Osmond,  Guille- 
min,  Charpy,  C.  E.  Guillaume — show  that  the  immu- 
tability even  of  bodies  supposed  to  be  the  most  rigid 
of  all,  such  as  glass,  the  metals,  steel,  and  brass,  is 
apparent  rather  than  real  Beneath  the  surface  of  the 
metal  that  seems  to  us  inert  there  is  a  swarming 
population  of  molecules,  displacing  each  other,  moving 


238  LIFE    AND    DEATH. 

about,  and  arranging  themselves  so  as  to  form  definite 
figures,  and  assuming  forms  adapted  to  the  conditions 
of  the  environment.  Sometimes  it  is  years  before 
they  arrive  at  the  state  of  ultimate  and  final  equili- 
brium— which  is  that  of  eternal  rest. 

However,  in  order  to  understand  these  facts  and 
their  interpretations,  it  is  necessary  to  pass  in  review 
the  fundamental  characteristics  of  living  beings.  It 
will  be  shown  that  these  very  characteristics  are  found 
in  inanimate  matter. 


CHAPTER  L 

UNIVERSAL  LIFE,     OPIXIOX5  OF  PHILOSOPHERS 
AXD  POETS. 

i.  Primitire  beliefe;  the  ideas  of  poets.— |  2.    Opinions  of 
from  brute  to  Grieg  bodies— Hoe 

by  summation— Ideas  of  philosopher  as  to  sensibility  and 
in  brate  bodies— The  general  principle  of 


§  i.  PRIMITIVE  BELIEFS.     IDEAS  OF  THE  POETS. 

The  teaching  of  science  as  to  the  analogies  between 
brute  bodies  and  living  bodies  accords  with  the  con- 
ceptions of  the  philosophers  and  the  fancies  of  the 
poets.  The  ancients  held  that  all  bodies  in  nature 
were  the  constituent  parts  of  a  universal  organism, 
the  macrocosm,  which  they  compared  to  the  human 
microcosm.  They  attributed  to  it  a  principle  of 
action,  the  psyche,  analogous  to  the  vital  principle, 
and  this  psyche  directed  phenomena;  and  also  an 
intelligent  principle,  the  MOHS,  analogous  to  the  soul, 
and  the  turns  served  for  the  comprehension  of  pheno- 
mena. This  universal  life  and  this  universal  soul 
played  an  important  part  in  their  metaphysical 
systems. 

239 


240  LIFE   AND   DEATH. 

It  was  the  same  with  the  poets.  Their  tendency 
has  always  been  to  attribute  life  to  Nature,  so  as  to 
bring  her  into  harmony  with  our  thoughts  and  feel- 
ings. They  seek  to  discover  the  life  or  soul  hidden 
in  the  background  of  things. 

"  Hark  to  the  voices.     Nothing  is  silent. 

Winds,  waves,  and  flames,  trees,  reeds,  and  rocks 
All  live;  all  are  instinct  with  soul." 

After  making  proper  allowance  for  emotional 
exaggeration,  ought  we  to  consider  these  ideas  as  the 
prophetic  divination  of  a  truth  which  science  is  only 
just  beginning  to  dimly  perceive?  By  no  means.  As 
Renan  has  said,  this  universal  animism,  instead  of 
being  a  product  of  refined  reflection,  is  merely  a 
legacy  from  the  most  primitive  of  mental  processes, 
a  residue  of  conceptions  belonging  to  the  childhood 
of  humanity.  It  recalls  the  time  when  men  conceived 
of  external  things  only  in  terms  of  themselves;  when 
they  pictured  each  object  of  nature  as  a  living  being. 
Thus,  they  personified  the  sky,  the  earth,  the  sea,  the 
mountains,  the  rivers,  the  fountains,  and  the  fields. 
They  likened  to  animate  voices  the  murmur  of  the 
forest : — 

".  .  .  The  oak  chides  and  the  birch 
Is  whispering.  .  .  . 
And  the  beech  murmurs.  .  .  . 

The  willow's  shiver,  soft  and  faint,  sounds  like  a  word. 
The  pine-tree  utters  mysterious  moans." 

For  primitive  man,  as  for  the  poet  of  all  times, 
everything  is  alive,  and  every  sound  is  due  to  a  being 
with  feelings  similar  to  our  own.  The  sighing  of  the 
breeze,  the  moan  of  the  wave  upon  the  shore,  the 


UNIVERSAL   LIFE.  241 

babbling  of  the  brook,  the  roaring  of  the  sea,  and  the 
pealing  of  the  thunder  are  nothing  less  than  sad, 
joyous,  or  angry  living  voices. 

These  impressions  were  embodied  in  ancient 
mythology,  the  graceful  beauty  of  which  does  not 
conceal  its  inadequacy.  Then  they  passed  into 
philosophy  and  approached  the  realm  of  science. 
Thales  believed  that  all  bodies  in  nature  were 
animate  and  living.  Origen  considered  the  stars  as 
actual  beings.  Even  Kepler  himself  attributed  to  the 
celestial  bodies  an  internal  principle  of  action,  which, 
it  may  be  said  in  passing,  is  contrary  to  the  law  of 
the  inertia  of  matter,  which  has  been  wrongly  ascribed 
to  him  instead  of  to  Galileo.  The  terrestrial  globe 
was,  according  to  him,  a  huge  animal,  sensitive  to 
astral  influences,  frightened  at  the  approach  of  the 
other  planets,  and  manifesting  its  terror  by  tempests, 
hurricanes,  and  earthquakes.  The  wonderful  flux  and 
reflux  of  the  ocean  was  its  breathing.  The  earth  had 
its  blood,  its  perspiration,  its  excretions ;  it  also  had 
its  foods,  among  which  was  the  sea  water  which  it 
absorbs  by  numerous  channels.  It  is  only  fair  to  add 
that  at  the  end  of  his  life  Kepler  retracted  these  vague 
dreams,  ascribing  them  to  the  influence  of  J.  C. 
Scaliger.  He  explained  that  by  the  soul  of  the 
celestial  bodies  he  meant  nothing  more  than  their 
motive  force. 


§  2.  OPINION  OF  THE  PHILOSOPHERS. 

Transition  from  Brute  to  Living  Bodies- — The 
lowering  of  the  barrier  between  brute  bodies  and 
living  bodies  began  with  those  philosophers  who 


242  t          LIFE   AND   DEATH. 

introduced    into   the   world    the   great   principles   of 
continuity  and  evolution. 

The  Principle  of  Continuity. — First  and  foremost 
we  must  mention  Leibniz.  According  to  the  teaching 
of  that  illustrious  philosopher,  as  interpreted  by  M. 
Fouillee,  "there  is  no  inorganic  kingdom,  only  a  great 
organic  kingdom,  of  which  mineral,  vegetable,  and 
animal  forms  are  the  various  developments.  .  .  . 
Continuity  exists  everywhere  throughout  the  world ; 
everywhere  is  life  and  organization.  Nothing  is 
dead ;  life  is  universal."  It  follows  that  there  is  no 
interruption  or  break  in  the  succession  of  natural 
phenomena;  that  everything  is  gradually  developed; 
and  finally,  that  the  origin  of  the  organic  being  must 
be  sought  in  the  inorganic.  Life,  properly  so  called, 
has  not,  in  fact,  always  existed  on  the  surface  of  the 
globe.  It  appeared  at  a  certain  geological  epoch,  in 
a  purely  inorganic  medium,  by  reason  of  favourable 
conditions.  The  doctrine  of  continuity  compels  us, 
however,  to  admit  that  it  pre-existed  on  the  globe 
under  some  rudimentary  form. 

The  modern  philosophers  who  are  imbued  with 
these  principles,  MM.  Fouillee,  L.  Bourdeau,  and  A. 
Sabatier,  express  themselves  in  similar  language. 
"  Dead  matter  and  living  matter  are  not  two  abso- 
lutely different  entities,  but  represent  two  forms  of 
the  same  matter,  differing  only  in  degree,  sometimes 
but  slightly."  When  it  is  only  a  matter  of  degree,  it 
cannot  be  held  that  these  views  are  opposed.  In- 
equalities must  not  be  interpreted  as  contrary  attri- 
butes, as  when  the  untrained  mind  considers  heat 
and  cold  as  objective  states,  qualitatively  opposed 
to  each  other. 

Continuity   by    Transition. — The   argument    which 


UNIVERSAL   LIFE.  243 

leads  us  to  remove  the  barrier  between  the  two  king- 
doms, and  to  consider  minerals  as  endowed  with  a 
sort  of  rudimentary  life,  is  the  same  as  that  which 
compels  us  to  admit  that  there  is  no  fundamental 
difference  between  natural  phenomena.  There  are 
transitions  between  what  lives  and  what  does  not; 
between  the  animate  being  and  the  brute  body.  And 
in  the  same  way  there  are  transitions  between  what 
thinks  and  what  does  not  think,  between  what  is 
thought  and  what  is  not  thought,  between  the  con- 
scious and  the  unconscious.  This  idea  of  insensible 
transition,  of  a  continuous  path  between  apparent 
antitheses,  at  first  arouses  an  insuperable  opposition 
in  minds  not  prepared  for  it  by  a  long  comparison  of 
facts.  It  is  slowly  realized,  and  finally  is  accepted  by 
those  who,  in  the  world  of  things,  follow  die  infinity 
of  gradations  presented  by  natural  phenomena.  The 
principle  of  continuity  comes  at  last  to  constitute,  as 
one  may  say,  a  mental  habit  Thus  the  man  of  science 
may  be  led,  like  the  philosopher,  to  entertain  the 
idea  of  a  rudimentary  form  of  life  animating  matter. 
He  may,  like  the  philosopher,  be  guided  by  this  idea; 
he  may  attribute  a  priori  to  brute  matter  all  the  really 
essential  qualities  of  living  beings.  But  this  must 
be  on  the  condition  that,  assuming  these  properties  to 
be  common,  he  must  afterwards  demonstrate  them  by 
means  of  observation  and  experiment  He  must  show 
that  molecules  and  atom*,  far  from  being  inert  and 
dead  masses,  are  in  reality  active  elements,  endowed 
with  a  kind  of  inferior  life,  which  is  manifested  by  all 
the  transformations  observed  in  brute  matter,  by 
attractions  and  repulsions,  by  movements  in  response 
to  external  stimuli,  by  variations  of  state  and  of 
equilibrium;  and  finally,  by  the  systematic  methods 


244  LIFE   AND   DEATH. 

according  to  which  these  elements  group  themselves, 
conforming  to  those  definite  types  of  structure  by 
means  of  which  they  produce  different  species  of 
chemical  compounds. 

Continuity  by  Summation.  —The  idea  of  summation 
leads  by  another  path  to  the  same  result.  It  is 
another  form  of  the  principle  of  continuity.  A  sum 
total  of  effects,  obscure  and  indistinct  in  themselves, 
produces  a  phenomenon  appreciable,  perceptible,  and 
distinct,  apparently,  but  not  really,  heterogeneous  in 
its  components.  The  manifestations  of  atomic  or 
molecular  activity  thus  become  manifestations  of  vital 
activity. 

This  is  another  consequence  of  the  teaching  of 
Leibniz.  For,  according  to  his  philosophical  theory, 
individual  consciousness,  like  individual  life,  is  the 
collective  expression  of  a  multitude  of  elementary 
lives  or  consciousnesses.  These  elements  are  in- 
appreciable because  of  their  low  degree,  and  the  real 
phenomenon  is  found  in  the  sum,  or  rather  the 
integral,  of  all  these  insensible  effects.  The  ele- 
mentary consciousnesses  are  harmonized,  unified, 
integrated  into  a  result  that  becomes  manifest,  just 
as  "  the  sounds  of  the  waves,  not  one  of  which  would 
be  heard  if  by  itself,  yet,  when  united  together  and 
perceived  at  the  same  instant,  become  the  resounding 
voice  of  the  ocean." 

Ideas  of  the  Philosophers  as  to  Sensibility  and  Con- 
sciousness in  Brute  Bodies. — The  philosophers  have 
gone  still  further  in  the  way  of  analogies,  and  have 
recognized  in  the  play  of  the  forces  of  brute  matter, 
particularly  in  the  play  of  chemical  forces,  a  mere 
rudiment  of  the  appetitions  and  tendencies  that  regu- 
late, as  they  believe,  the  functional  activity  of  living 


UNIVERSAL   LIFE.  245 

beings — a  trace,  as  it  were,  of  their  sensibility.  To 
them  reactions  of  matter  indicate  the  existence  of  a 
kind  of  Jiedonic  consciousness — i.e.,  a  consciousness 
reduced  simply  to  a  distinction  between  comfort  and 
discomfort,  a  desire  for  good  and  repulsion  from  evil, 
which  they  suppose  to  be  the  universal  principle  of  all 
activity.  This  was  the  view  held  by  Empedocles  in 
antiquity;  it  was  that  of  Diderot,  of  Cabanis,  and,  in 
general,  of  the  modern  materialistic  school,  eager  to 
find,  even  in  the  lowest  representatives  of  the 
inorganic  world,  the  first  traces  of  the  vitality  and 
intellectual  life  which  blossom  out  at  the  top  of  the 
scale  in  the  living  world. 

Similar  ideas  are  clearly  seen  in  the  early  history  of 
all  natural  sciences.  It  was  this  same  principle  of 
appetition,  or  of  love  and  of  repulsion  or  hate  that, 
under  the  names  of  affinity,  selection,  and  incom- 
patibility, was  thought  to  direct  the  transformations  of 
bodies  when  chemistry  first  began ;  when  Boerhaave, 
for  example,  compared  chemical  combinations  to 
voluntary  and  conscious  alliances,  in  which  the 
respective  elements,  drawn  together  by  sympathy, 
contracted  appropriate  marriages. 

General  Principle  of  tlie  Homogeneity  of  the  Complex 
and  its  Components. — The  assimilation  of  brute  bodies 
to  living  bodies,  and  of  the  inorganic  kingdom  to  the 
organic,  was,  in  the  mind  of  these  philosophers,  the 
natural  consequence  of  positing  a  priori  the  principles 
of  continuity  and  evolution.  There  is,  however,  a 
principle  underlying  these  principles.  This  principle 
is  not  expressed  explicitly  by  the  philosophers;  it  is 
not  formulated  in  precise  terms,  but  is  more  or  less 
unconsciously  implied;  it  is  everywhere  applied.  It, 
however,  may  be  clearly  seen  behind  the  apparatus  of 


246  LIFE   AND    DEATH. 

philosophical  argument.  It  is  the  assertion  that  no 
arrangement  or  combination  of  elements  can  put 
forth  any  new  activity  essentially  different  from  the 
activities  of  the  elements  of  which  it  is  composed. 
Man  is  living  clay,  say  Diderot  and  Cabanis;  and, 
on  the  other  hand,  he  is  a  thinking  being.  As  it  is 
impossible  to  produce  tliat  wliicJi  tJiinks  from  tliat  wliicli 
does  not  think,  the  clay  must  possess  a  rudiment  of 
thought.  But  is  there  not  another  alternative  ?  May 
not  the  new  phenomenon,  thought,  be  the  effect  of 
the  arrangement  of  this  clay?  If  we  exclude  this 
alternative,  we  must  then  consider  arrangement  and 
organization  as  incapable  of  producing  in  arranged 
and  organized  matter  a  new  property  different  from 
that  which  it  presented  before  such  arrangement. 
Living  protoplasm,  says  another,  is  merely  an 
assemblage  of  brute  elements;  "these  brute  elements 
must  therefore  possess  a  rudiment  of  life."  This  is 
the  same  implied  supposition  which  we  have  just 
considered ;  if  life  is  not  the  basis  of  each  element,  it 
cannot  result  from  their  simple  assemblage. 

Man  and  animals  are  combinations  of  atoms,  says 
M.  le  Dantec.  It  is  more  natural  to  admit  that 
human  consciousness  is  the  result  of  the  elementary 
consciousness  of  the  constituent  atoms  than  to  con- 
sider it  as  resulting  from  construction  by  means 
of  elements  with  no  consciousness.  "  Life,"  says 
Haeckel,  "is  universal;  we  could  not  conceive  of  its 
existence  in  certain  aggregates  of  matter  if  it  did  not 
belong  to  their  constituent  elements."  Here  the 
postulate  is  almost  expressed. 

The  argument  is  always  the  same ;  even  the  same 
Words  are  used  :  the  fundamental  hypothesis  is  the 
same  j  only  it  remains  more  or  less  unexpressed, 


UNIVERSAL    LIFE.  247 

more  or  less  unperceived.  It  may  be  stated  as 
follows  : — Arrangement,  assemblage,  construction,  and 
aggregation  are  powerless  to  bring  to  light  in  the 
complex  anything  new  and  essentially  heterogeneous 
to  what  already  exists  in  the  elements.  Reciprocally, 
grouping  reveals  in  a  complex  n  property  and 
character  which  is  the  gradual  development  of  an 
analogous  property  and  character  in  the  elements. 
It  is  in  this  sense  that  there  exists  a  collective  soul  in 
crowds,  the  psychology  of  which  has  been  discussed 
by  M.  G.  Le  Bon.  In  the  same  way,  many  sociolo- 
gists, adopting  the  views  advanced  by  P.  de  Lilienfeld 
in  1865,  attribute  to  nations  a  formal  individuality, 
after  the  type  of  that  possessed  by  each  of  their 
constituent  members.  M.  Izolet  considers  society 
as  an  organism,  which  he  calls  a  "  hyperzoan. 
Herbert  Spencer  has  developed  the  comparison  of 
the  collective  organism  with  the  individual  organism, 
insisting  on  their  resemblances  and  differences.  Th. 
Ribot  has  dwelt,  in  particular,  on  the  resemblances. 

The  postulate  that  we  have  clearly  stated  here  is 
accepted  by  many  as  an  axiom.  But  it  is  not  an 
axiom.  When  we  say  that  there  is  nothing  in  the 
complex  that  cannot  be  found  in  the  parts,  we  think 
we  are  expressing  a  self-evident  truth ;  but  we  are, 
in  fact,  merely  stating  an  hypothesis.  It  is  assumed 
that  arrangement,  aggregation,  and  complicated  and 
skilful  grouping  of  elements  can  produce  nothing 
really  new  in  the  order  of  phenomena.  And  this  is 
an  assertion  that  requires  verification  in  each  par- 
ticular case. 

TJte  Principle  of  Continuity,  a  Consequence  of  the 
Preceding. — Let  us  apply  this  principle  to  the  beings 
in  nature.  All  beings  in  nature  are,  according  to 


248  LIFE   AND    DEATH. 

current  ideas,  arrangements,  aggregates,  or  groupings 
of  the  same  universal  matter,  that  is  to  say,  of  the 
same  simple  chemical  bodies.  It  results  from  the 
preceding  postulate  that  their  activities  can  only  differ 
in  degree  and  form,  and  not  fundamentally.  There 
is  no  essential  difference  of  nature  between  the 
activities  of  various  categories  of  beings,  no  hetero- 
geneity, no  discontinuity.  We  may  pass  from  one  to 
another  without  coming  to  an  hiatus  or  impassable 
gulf.  The  law  of  continuity  thus  appears  as  a  simple 
consequence  of  the  fundamental  postulate.  And  so 
it  is  with  the  law  of  evolution,  for  evolution  is  merely 
continuity  of  action. 

Such  are  the  origins  of  the  philosophical  doctrine 
which  universalizes  life  and  extends  it  to  all  bodies 
in  nature. 

It  may  be  remarked  that  this  doctrine  is  not 
confined  to  any  particular  school  or  sect.  Leibniz 
was  by  no  means  a  materialist,  and  he  endowed  his 
mundane  elements,  his  monads,  not  only  with  a  sort 
of  life,  but  even  with  a  sort  of  soul.  Father  Bosco- 
vitch,  Jesuit  as  he  was,  and  professor  in  the  college  of 
Rome,  did  not  deny  to  his  indivisible  points  a  kind  of 
inferior  vitality.  St.  Thomas,  too,  the  angelical 
doctor,  attributed,  according  to  M.  Gardair,  to 
inanimate  substances  a  certain  kind  of  activity, 
inborn  inclinations,  and  a  real  appetition  towards 
certain  acts. 


CHAPTER  II. 

ORIGIN   OF  BRUTE  MATTER  IN   LIVING   MATTER. 

Spontaneous  generation:  an  episode  in  the  history  of  the 
globe  —  Verification  of  the  identity  between  brute  and 
living  matter  —  Slow  identification  —  Rapid  identification 
— Contrary  opinion — Hypothesis  of  cosmozoa  ;  cosmic 
panspermia — Hypothesis  of  pyrozoa. 

THERE  should  be  two  ways  of  testing  the  doctrine  of 
the  essential  identity  of  brute  and  living  matter — 
one  slow  and  more  laborious,  the  other  more  rapid 
and  decisive. 

Identification  of  tfie  Two  Matters,  Brute  and 
Living. — The  laborious  method,  which  we  will  be 
obliged  to  follow,  consists  in  the  attentive  examina- 
tion of  the  various  activities  by  which  life  is 
manifested,  and  in  finding  more  or  less  crude 
equivalents  for  them  in  all  brute  beings,  or  in  certain 
of  them. 

Rapid  Verification.  Spontaneous  Generation. — The 
rapid  and  decisive  method,  which,  unhappily,  is 
beyond  our  resources,  would  consist  in  showing  un- 
questionable, clearly  marked  life,  the  superior  life, 
arising  from  the  kind  of  inferior  life  that  is  attributed 
to  matter  in  general.  It  would  be  necessary  com- 
pletely to  construct  in  all  its  parts,  by  a  suitable 
combination  of  inorganic  materials,  a  single  living 
being,  even  the  humblest  plant  or  the  most  rudi- 
249 


250  LIFE    AND    DEATH. 

mentary  animal.  This  would  indeed  be  an  irrefutable 
proof  that  the  germs  of  all  vital  activity  are  contained 
in  the  molecular  activity  of  brute  bodies,  and  that 
there  is  nothing  essential  to  the  latter  that  is  not 
found  in  the  former. 

.Unhappily  this  demonstration  cannot  be  given. 
Science  furnishes  no  example  of  it,  and  we  are  forced 
to  have  recourse  to  the  slow  method. 

The  question  here  involved  is  that  of  spontaneous 
generation.  It  is  well  known  that  the  ancients 
believed  in  spontaneous  generation,  even  for  animals 
high  in  the  scale  of  organization.  According  to 
Van  Helmont,  mice  could  be  born  by  some  incom- 
prehensible fermentation  in  dirty  linen  mixed  with 
wheat.  Diodorus  speaks  of  animal  forms  which  were 
seen  to  emerge,  partly  developed,  from  the  mud  of 
the  Nile.  Aristotle  believed  in  the  spontaneous  birth 
of  certain  fishes.  This  belief,  though  rejected  as  to 
the  higher  forms,  was  for  a  long  time  held  with 
regard  to  the  lower  forms  of  animals,  and  to  insects — 
such  as  the  bees  which  the  shepherd  of  Virgil  saw 
coming  out  from  the  flanks  of  the  dead  bullock — 
flies  engendered  in  putrefying  meat,  fruit  worms  and 
intestinal  worms ;  finally,  with  regard  to  infusoria 
and  the  most  rudimentary  vegetables.  The  hypo- 
thesis of  the  spontaneous  generation  of  the  living 
being  at  the  expense  of  the  materials  of  the  ambient 
medium  has  been  successively  driven  from  one 
classificatory  group  to  another.  The  history  of  the 
sciences  of  observation  is  also  a  history  of  the  con- 
futation of  this  theory.  Pasteur  gave  it  the  finishing 
stroke,  when  he  showed  that  the  simplest  micro- 
organisms obeyed  the  general  law  which  declares 
that  the  living  being  is  formed  only  by  filiation — that 


ORIGIN    OF    BRUTE    MATTER.  251 

is  to  say,  by  the  intervention  of  a  pre-existing  living 
organism. 

Spontaneous  Generation  an  Episode  in  tfie  History 
of  the  Globe. — Though  we  have  been  unable  to  effect 
spontaneous  generation  up  to  the  present,  it  has  been 
referred  by  Haeckel  to  a  more  or  less  distant  past,  to 
the  time  when  the  cooling  of  the  globe,  the  solidifica- 
tion of  its  crust,  and  the  condensation  of  aqueous 
vapour  upon  its  surface  created  conditions  compatible 
with  the  existence  of  li\yng  beings  similar  to  those 
with  which  we  are  acquainted.  Lord  Kelvin  has 
fixed  these  geological  events  as  occurring  from  twenty 
to  forty  million  years  ago.  Then  circumstances 
became  propitious  for  the  appearance  of  the  first 
organisms,  whence  were  successively  derived  those 
which  now  people  the  earth  and  the  waters. 

Circumstances  favourable  to  the  appearance  of  the 
first  beings  apparently  occurred  only  in  a  far  distant 
past ;  but  most  physiologists  admit  that  if  we  knew 
exactly  these  circumstances,  and  could  reproduce 
them,  we  might  also  expect  to  produce  their  effect — 
namely,  the  creation  of  a  living  being,  formed  in  all 
its  parts,  developed  from  the  inorganic  kingdom. 
To  all  those  who  held  this  view  the  impotence  of 
experiment  at  the  present  time  is  purely  temporary. 
It  is  comparable  to  that  of  primitive  men  before  the 
time  of  Prometheus ;  they,  not  knowing  how  to 
produce  fire,  could  only  get  it  by  transmitting  it 
from  one  to  another.  It  is  due  to  the  inadequacy 
of  our  knowledge  and  the  weakness  of  our  means ;  it 
does  not  contradict  the  possibility  of  the  fact 

Contrary  Opinion.  Life  did  not  Originate  on  our 
Globe. — But  all  biologists  do  not  share  this  opinion. 
Some,  and  not  the  least  eminent,  hold  it  to  be  an 


252  LIFE    AND    DEATH. 

established  fact  that  it  is  impossible  for  life  to  arise 
from  a  concurrence  of  inorganic  materials  and  forces. 
This  was  the  opinion  of  Ferdinand  Cohn,  the  great 
botanist ;  of  H.  Richter,  the  Saxon  physician,  and  of 
W.  Preyer,  a  physiologist  well  known  from  his 
remarkable  researches  in  biological  chemistry. 
According  to  these  scientists,  life  on  the  surface  of 
the  globe  cannot  have  appeared  as  a  result  of  the 
reactions  of  brute  matter  and  the  forces  that  continue 
to  control  it. 

According  to  F.  Cohn  and  II.  Richter,  life  had  no 
beginning  on  our  planet.  It  was  transported  to  the 
earth  from  another  world,  from  the  cosmic  medium, 
under  the  form  of  cosmic  germs,  or  cosmozoa,  more 
or  less  comparable  to  the  living  cells  with  which  we 
are  acquainted.  They  may  have  made  the  journey 
either  enclosed  in  meteorites,  or  floating  in  space  in 
the  form  of  cosmic  dust.  The  theory  in  question 
has  been  presented  in  two  forms  : — The  Hypothesis  of 
Meteoric  Cosmozoa,  by  a  French  writer,  the  Count 
de  Salles-Guyon ;  and  that  of  cosmic  panspennia 
brought  forward  in  1865  and  1872  by  F.  Cohn  and 
H.  Richter. 

Hypothesis  of  the  Cosinozoa. — The  hypothesis  of 
the  cosmozoa,  living  particles,  protoplasmic  germs 
emanating  from  other  worlds  and  reaching  the  earth 
by  means  of  aerolites,  is  not  so  destitute  of  probability 
as  one  might  at  first  suppose.  Lord  Kelvin  and 
Helmholtz  gave  it  the  support  of  their  high  authority. 
Spectrum  analysis  shows  in  cometary  nebulae  the 
four  or  five  lines  characteristic  of  hydro-carbons. 
Cosmic  matter,  therefore,  contains  compounds  of 
carbon,  substances  that  are  especially  typical  of 
organic  chemistry.  Besides,  carbon  and  a  sort  of 


ORIGIN  OF  BRUTE   MATTER.  253 

humus  have  been  found  in  several  meteorites,  To 
the  objection  that  these  aerolites  are  heated  while 
passing  through  our  atmosphere,  Helmholtz  replies 
that  this  elevation  of  temperature  may  be  quite 
superficial  and  may  allow  micro-organisms  to  subsist 
in  their  interior.  But  other  objections  retain  their 
force : — First,  that  of  M.  Verwom,  who  considers  the 
hypothesis  of  cosmic  germs  as  inconsistent  with  the 
laws  of  evolution  ;  and  that  of  L,  Errera,  who  denies 
that  the  conditions  necessary  for  life  exist  in  inter- 
planetary bodies. 

Hypothesis  of  Cosmic  Panspcrmia,  —  Du  Bois- 
Reymond  has  given  the  name  of  cosmic  paxspcrmia 
to  a  theory  very  similar  to  the  preceding,  formulated 
by  F.  Cohn  in  1872.  The  first  living  germs  arrived 
en  our  globe  mingled  with  the  cosmic  dust  that 
floats  in  space  and  falls  slowly  to  the  surface  of  the 
earth.  li  Errera  observes  that  if  they  escape  by 
this  gentle  fall  the  dangerous  heating  of  meteorites, 
they  still  remain  exposed  to  the  action  of  the  photic 
rays,  which  is  generally  destructive  to  germs. 

Hypothesis  of  Pjrosoa, — W.  Preyer  declined  to 
accept  this  cosmic  transmigration  of  the  simplest 
living  beings,  nor  would  he  allow  the  intervention  of 
other  worlds  into  the  history  of  our  own.  Life, 
according  to  him,  must  have  existed  from  all  time, 
even  when  the  globe  was  an  incandescent  mass. 
But  it  was  not  the  same  life  as  at  present.  Vitality 
must  have  undergone  many  profound  changes  in  the 
course  of  ages.  The  pyrosoa^  the  first  living  beings, 
vulcanians,  were  very  different  from  the  beings  of 
the  present  day  that  are  destroyed  by  a  slight 
elevation  of  temperature.  No  doubt  this  theory  of 
pyrozoa,  proposed  by  W.  Preyer  in  1872,  seems 


254  LIFE   AND   DEATH. 

quite  chimerical,  and  akin  to  Kepler's  dreamy  visions. 
But  in  a  certain  way  it  accords  with  contemporary 
ideas  concerning  the  life  of  matter.  It  is  related  to 
them  by  the  evolution  which  it  implies  in  the  materials 
of  the  terrestrial  globe. 

According  to  Preyer,  primitive  life  existed  in  fire. 
Being  igneous  masses  in  fusion,  the  pyrozoa  lived 
after  their  own  manner;  their  vitality,  slowly  modified, 
assumed  the  form  which  it  presents  to-day.  Yet,  in 
this  profound  transformation  their  number  has  not 
varied,  and  the  total  quantity  of  life  in  the  universe 
has  remained  unchanged. 

Here  we  recognize  the  ideas  of  'Buffon.  These 
cosmozoa,  these  pyrozoa,  have  a  singular  resemblance 
to  the  organic  molecules  of  "live  matter"  of  the 
illustrious  naturalist  —  distributed  everywhere,  in- 
destructible, and  forming  living  structures  by  their 
concentration. 

But  we  must  leave  these  scientific  or  philosophical 
theories,  and  come  to  arguments  based  upon  facts. 

It  is  in  a  spirit  quite  different  from  that  of  the 
poets,  the  metaphysicians,  and  the  more  or  less 
philosophical  scientists  that  the  science  of  our  days 
looks  at  the  more  or  less  obscure  vitality  of  inanimate 
bodies.  It  claims  that  we  may  recognize  in  them, 
in  a  more  or  less  rudimentary  state,  the  action 
of  the  factors  which  intervene  in  the  case  of  living 
beings,  the  manifestation  of  the  same  fundamental 
properties. 


CHAPTER  III. 

ORGANIZATION   AND  CHEMICAL  COMPOSITION  OF 
LIVING  AND  BRUTE  MATTER. 

Laws  of  the  organization  and  of  the  chemical  composition  of 
living  beings — Relative  value  of  these  lavs;  vital  pheno- 
mena in  crashed  protoplasm — Vital  phenomena  in  brute 
bodies, 

Enumeration  of  ike  Principal  Characters  of  Living 
Beings. — The  programme  which  we  have  just  sketched 
compels  us  to  look  in  the  brute  being  for  the  pro- 
perties of  living  beings.  What,  then,  are,  in  fact,  the 
characteristics  of  an  authentic,  complete,  living  being  ? 
What  are  its  fundamental  properties?  We  have 
enumerated  them  above  as  follows : —  A  certain 
chemical  composition,  which  is  that  of  living  matter : 
a  structure  or  organization ;  a  specific  form ;  an 
evolution  which  has  a  duration,  that  of  life,  and  an 
end,  death ;  a  property  *  of  growth  or  nutrition ;  a 
property  of  reproduction.  Which  of  these  characters 
counts  for  most  in  the  definition  of  life  ?  Are  they 
all  equally  necessary  ?  If  some  of  them  were  wanting, 
would  that  justify  the  transference  of  a  being,  who 
might  possess  the  rest,  from  the  animate  world  to 
that  of  minerals  ?  This  is  precisely  the  question  that 
is  under  consideration. 

Organization  and  Chemical  Composition  of  Living 
Beings. — All  that  we  know  concerning  the  constitution 
255 


256  LIFE   AND   DEATH. 

of  living  matter  and  its  organization  is  summed  up  in 
the  laws  of  the  cliemical  unity  and  the  morphological 
unity  of  living  beings  (v.  Book  III.).  These  laws  seem 
to  be  a  legitimate  generalization  from  all  the  facts 
observed.  The  first  states  that  the  phenomena  of 
life  are  manifested  only  in  and  through  living  matter, 
protoplasm — i.e.,  in  and  through  a  substance  which 
has  a  certain  chemical  and  physical  composition. 
Chemically  it  is  a  proteid  complexus  with  a  hexonic 
nucleus.  Physically  it  shows  a  frothy  structure 
analogous  to  that  resulting  from  the  mixture  of  two 
granular,  immiscible  liquids,  of  different  viscosities. 
The  second  law  states  that  the  phenomena  of  life 
can  only  be  maintained  in  a  protoplasm  which  has 
the  organization  of  the  complete  cell,  with  its  cellular 
body  and  nucleus. 

Relative  Value  of  these  Laws.  Exceptions. — What 
is  the  signification  of  these  laws  of  the  chemical 
composition  and  organization  of  living  beings? 
Evidently  that  life  in  all  its  plenitude  can  only  exist 
and  be  perpetuated  under  their  protection.  If  these 
laws  were  absolute,  if  it  were  true  that  no  life  were 
possible  but  in  and  through  albuminous  protoplasm, 
but  in  and  through  the  cell,  the  problem  of  "  the  life 
of  matter"  would  be  decided  in  the  negative. 

May  it  not  happen,  however,  that  fragmentary  and 
incomplete  vital  manifestations,  progressive  traces 
of  a  true  life,  may  occur  under  different  conditions; 
for  example,  in  matter  which  is  not  protoplasm,  and 
in  a  body  which  has  a  structure  differing  from  that 
of  a  cell — that  is  to  say,  in  a  being  which  would  be 
neither  animal  nor  plant?  We  must  seek  the  answer 
to  this  question  by  an  appeal  to  experiment. 

Without  leaving  the  animal   and  vegetable  king- 


ORGANIZATION   AND   CHEMICAL   COMPOSITION.      257 

doms — i.e.,  real  living  beings — we  already  see  less 
rigour  in  the  laws  governing  chemical  constitution 
and  cellular  organization. 

Experiments  in  merotomy — i.e.,  in  amputation — 
carried  out  on  the  nervous  element  by  Waller,  on 
infusoria  by  Brandt,  Gruber,  Balbiani,  Xussbaum, 
and  Verworn,  show  us  the  necessity  of  the  presence 
of  the  cellular  body  and  the  nucleus — i.e.,  of  the  in- 
tegrity of  the  cell.  But  they  also  teach  us  that  when 
that  integrity  no  longer  exists  death  does  not  imme- 
diately follow.  A  part  of  the  vital  functions  continues 
to  be  performed  in  denucleated  protoplasm,  in  a  cell 
which  is  mutilated  and  incomplete. 

Vital  Phenomena  in  Crushed  Protoplasm. — It  is 
true  also  that  grinding  and  crushing  suppress  the 
greater  part  of  the  functions  of  the  cell.  But  tests 
with  pulps  of  various  organs  and  with  those  of  certain 
yeasts  also  show  that  protoplasm,  even  though  ground 
and  disorganized,  cannot  be  considered  as  inert,  and 
that  it  still  exhibits  many  of  its  characteristic  pheno- 
mena ;  for  example,  the  production  of  diastases,  the 
specific  agents  of  vital  chemistry.  Finally,  while  we 
do  not  know  enough  about  the  actions  of  which  the 
secondary  elements  of  protoplasm — its  granulations, 
its  filaments — are  capable,  which  this  or  that  method 
of  destruction  may  bring  to  light,  at  least  we  kno\v 
that  actions  of  this  kind  exist. 

To  sum  up,  we  are  far  from  being  able  to  deny  that 
rudimentary,  isolated  vital  acts  may  be  produced  by 
the  various  bodies  that  result  from  the  dismember- 
ment of  protoplasm.  The  integrity  of  the  cellular 
organization,  even  the  integrity  of  protoplasm  itself, 
are  therefore  not  indispensable  for  these  partial 
manifestations  of  vitality. 


258  LIFE   AND   DEATH. 

Besides,  biologists  admit  that  there  exist  with- 
in the  protoplasm  aliquot  parts,  elements  of  an 
inferior  order,  which  possess  special  activities. 
These  secondary  elements  must  have  the  principle 
of  their  activity  within  themselves.  Such  are  the 
biophors  to  which  Weismann  attributes  the  vital 
functions  of  the  cell,  nutrition,  growth,  and  multipli- 
cation. If  there  are  biophors  within  the  cell,  we 
may  imagine  them  outside  the  cell,  and  since  they 
carry  within  themselves  the  principle  of  their  activity 
they  may  exercise  it  in  an  independent  manner. 
Unhappily  the  biophors,  and  other  constituent  ele- 
ments of  that  kind,  are  purely  hypothetical.  They 
are  like  Darwin's  gemmules,  Altmann's  bioblasts,  and 
the  pangens  of  De  Vries.  They  have  no  relation  to 
facts  of  observation  and  to  real  existence. 

Vital  Phenomena  in  Brute  Bodies. — There  is  no 
doubt  that  certain  phenomena  of  vitality  may  occur 
outside  of  the  cellular  atmosphere.  And  carrying 
this  further,  we  may  admit  that  they  may  be  pro- 
duced in  certain  slightly  organized  bodies  (crushed 
cells),  and  then  in  certain  unorganized  bodies  in 
certain  brute  beings.  In  every  case  it  is  certain  that 
effects  are  produced  at  any  rate  similar  to  those  which 
are  characteristic  of  living  matter.  It  is  for  observation 
and  experiment  to  decide  as  to  the  degree  of  similarity, 
and  their  verdict  is  that  the  similarity  is  complete. 
The  crystals  and  the  crystalline  germs  studied  by 
Ostwald  and  Tammann  are  the  seat  of  phenomena 
which  are  quite  comparable  to  those  of  vitality. 


CHAPTER  IV. 

EVOLUTION    AND   MUTABILITY  OF    LIVING    MATTER 
AND  BRUTE  MATTER. 

Supposed  immobility  of  brute  bodies — Mobility  and  mutability 
of  the  sidereal  world. — §  r.  The  movement  of  particles  and 
molecules  in  brute  bodies — The  internal  movements  of 
brute  bodies — Kinetic  conception  of  molecular  motion — 
Reality  of  the  motion  of  particles — Comparison  of  the 
activity  of  particles  with  vital  activity. — §  2.  Brownian 
movement — Its  existence — Its  character— Its  independence 
of  the  nature  of  the  bodies  and  of  the  nature  of  the  environ- 
ment— Its  indefinite  duration — Its  independence  of  external 
conditions — The  Brownian  movement  must  be  the  first 
stage  of  molecular  motion.— £  3.  Motion  of  panicles — 
Migration  of  material  panicles  —  Migration  under  the 
action  of  weight ;  of  diffusion;  of  electrolysis;  of  mechanical 
pressure. — §  4.  Internal  activity  of  alloys — Their  structure — 
Changes  produced  by  deforming  agencies — Slow  return  to 
equilibrium — Residual  effect — Effect  of  annealing;  effect 
of  stretching — Nickel  steel — Colour  photography — Con- 
clusion— Relations  of  the  environment  to  the  living  or  brute 


ONE  of  the  most  remarkable  characteristics  of  a  living 
being  is  its  evolution.  It  undergoes  a  continuous 
change.  It  starts  from  something  very  small;  it 
assumes  a  configuration  and  grows ;  in  most  cases 
it  declines  and  disappears,  having  followed  a  course 
which  may  be  predicted — a  sort  of  ideal  trajectory. 

Supposed  Immobility  of  Brute  Bodies. — It  may  be 
asked  whether  this  evolution,  this  directed  mobility, 
259 


260  LIFE   AND   DEATH. 

is  so  exclusively  a  feature  of  the  living  being  as  it 
appears,  and  if  many  brute  bodies  do  not  present 
something  analogous  to  it.  We  may  answer  in  no 
uncertain  tones. 

Bichat  was  wrong  when  he  contrasted  in  this 
respect  brute  bodies  with  living  bodies.  Vital 
properties,  he  said,  are  temporary;  it  is  their  nature 
to  be  exhausted ;  in  time  they  are  used  up  in  the 
same  body.  Physical  properties,  on  the  contrary,  are 
eternal.  Brute  bodies  have  neither  a  beginning  nor 
an  inevitable  end,  neither  age,  nor  evolution;  they 
remain  as  immutable  as  death,  of  which  they  are  the 
image. 

Mobility  and  Mutability  of  the  Sidereal  World. — 
This  is  not  true,  in  the  first  place,  of  the  sidereal 
bodies.  The  ancients  held  the  sidereal  world  to  be 
immutable  and  incorruptible.  The  doctrine  of  the 
incorruptibility  of  the  heavens  prevailed  up  to  the 
seventeenth  century.  The  observers  who  at  that 
epoch  directed  towards  the  heavens  the  first  telescope, 
which  Galileo  had  just  invented,  were  struck  with 
astonishment  at  discovering  a  change  in  that  celestial 
firmament  which  they  had  hitherto  believed  incor- 
ruptible, and  at  perceiving  a  new  star  that  appeared 
in  the  constellation  Ophiuchus.  Such  changes  no 
longer  surprise  us.  The  cosmogonic  system  of 
Laplace  has  become  familiar  to  all  cultivated  minds, 
and  every  one  is  accustomed  to  the  idea  of  the  con- 
tinual mobility  and  evolution  of  the  celestial  world. 
"  The  stars  have  not  always  existed,"  writes  M.  Faye ; 
"  they  have  had  a  period  of  formation  ;  they  will 
likewise  have  a  period  of  decline,  followed  by  final 
extinction." 

Thus  all  the  bodies  of  inanimate  nature  are  not 


EVOLtmOSC  AXD  MUTABILITY  OF  MATTER.    261 

eternal  and  immutable;  the  celestial  bodies  are 
eminently  susceptible  of  evolution,  slow  indeed  with 
that  we  observe  on  the  surface  of  our  globe;  but  this 
disproportion,  corresponding  to  the  immensity  of 
time  and  of  cosmic  spaces  as  compared  with  terres- 
trial measurements,  should  not  mislead  us  as  to  the 
fundamental  analogy  of  the  phenomena. 


I  i.  THE  MOVEMEXT  OF  PARTICLES  AXD  MOLE- 
CULES ra  BRCTE  BODIES. 

It  is  not  only  in  celestial  spaces  that  we  must 
search  for  that  mobility  of  brute  matter  which  imitates 
the  mobility  of  living  matter.  In  order  to  find  it  we 
have  only  to  look  about  us,  or  to  inquire  from 
physicists  and  chemists. 

As  far  as  geologists  are  concerned,  3*L  le  Dantec 
tells  us  somewhere  of  one  who  divided  minerals  into 
living  rocks — rocks  capable  of  change  of  structure,  of 
evolution  under  the  influence  of  atmospheric  causes ; 
and  dead  rocks — rocks  which,  like  clay,  have  found  at 
the  end  of  all  their  changes  a  final  state  of  repose. 
Jerome  Cardan,  a  celebrated  scientist  of  the  sixteenth 
century,  at  once  mathf»fni»ti*~ian>  naturalist,  and 
physician,  declared  not  only  that  stones  live,  but 
that  they  suffer  from  disease,  grow  old,  and  die. 
The  jewellers  of  the  present  day  use  similar  language 
of  certain  precious  stones;  the  torquoise,  for  example. 

The  alchemists  carried  these  ideas  to  an  extreme. 
It  is  not  necessary  here  to  recall  the  past,  to  evoke 
the  hermetic  beliefs  and  the  dreams  of  the  alchemists, 
who  held  that  the  different  lands  of  matter  lived, 
developed,  and  were  transmuted  into  each  other. 


262  LIFE    AND    DEATH. 

I  refer  to  precise  and  recent  data,  established  by 
the  most  expert  investigators,  and  related  by  one  of 
them,  Charles  Edward  Guillaume,  some  years  ago, 
before  the  Societe  lielvttique  des  Sciences  naturcllcs. 
These  data  show  that  determinate  forms  of  matter 
may  live  and  die,  in  the  sense  that  they  may  be 
slowly  and  continuously  modified,  always  in  the  same 
direction,  until  they  have  attained  an  ultimate  and 
definitive  state  of  eternal  repose. 

The  Internal  Movements  of  Bodies. — Swift's  reply  to 
an  idle  fellow  who  spoke  slightingly  of  work  is  well 
known.  "  In  England,"  said  the  author  of  Gulliver's 
Travels,  "  men  work,  women  work,  horses  work, 
oxen  work,  water  works,  fire  works,  and  beer  works ; 
it  is  only  the  pig  who  does  nothing  at  all;  he  must, 
therefore,  be  the  only  gentleman  in  England."  We 
know  very  well  that  English  gentlemen  also  work. 
Indeed,  everybody  and  everything  works.  And  the 
great  wit  was  nearer  right  than  he  supposed  in  com- 
paring men  and  things  in  this  respect.  Everything 
is  at  work;  everything  in  nature  strives  and  toils,  at 
every  stage,  in  every  degree.  Immobility  and  repose 
in  the  case  of  natural  things  are  usually  deceptive; 
the  seeming  quietude  of  matter  is  caused  by  our 
inability  to  appreciate  its  internal  movements.  Be- 
cause of  their  minuteness  we  do  not  perceive  the 
swarming  particles  that  compose  it,  and  which,  under 
the  impassible  surface  of  the  bodies,  oscillate,  displace 
each  other,  move  to  and  fro,  and  group  themselves 
into  forms  and  positions  adapted  to  the  conditions 
of  the  environment.  In  comparison  with  these 
microscopic  elements  we  are  like  Swift's  giant  among 
the  Lilliputians;  and  this  is  far  from  being  a  suffi- 
ciently forcible  comparison. 


EVOLUTION   AND   MUTABILITY  OF   MATTER.     263 

Kinetic  Conception  of  Molecular  Motion. — The  idea 
of  this  peculiar  form  of  motion  is  by  no  means  new  to 
us.  We  were  familiarized  with  it  in  scientific  theories 
during  our  school  days.  The  atomic  theory  teaches 
us  that  matter  behaves,  from  a  chemical  point  of 
view,  as  if  it  were  divided  into  molecules  and  atoms. 
The  kinetic  theory  explains  the  constitution  of  gases 
and  the  effects  of  heat  by  supposing  that  these 
particles  are  endowed  with  movements  of  rotation 
and  displacement  The  wave  theory  explains  photic 
phenomena  by  supposing  peculiar  vibratory  move- 
ments in  a  special  medium — the  ether.  But  these 
are  merely  hypotheses  which  are  not  at  all  necessary; 
they  are  the  images  of  things,  not  the  things  them- 
selves, 

Reality  of  tJi£  Motion  of  Particles. — Here  there  is 
no  question  of  hypotheses.  This  internal  agitation, 
this  interior  labour,  this  incessant  activity  of  matter 
are  positive  facts,  an  objective  reality.  It  is  true  that 
when  the  chemical  or  mechanical  equilibrium  of 
bodies  is  disturbed  it  is  only"  restored  more  or  less 
slowly.  Sometimes  days  and  years  are  required 
before  it  is  regained.  Scarcely  do  they  attain  this 
relative  repose  when  they  are  again  disturbed,  for  the 
environment  itself  is  not  fixed;  it  experiences  varia- 
tions which  react  in  their  turn  upon  the  body  under 
consideration ;  and  it  is  only  at  the  end  of  these 
variations,  at  the  end  of  their  respective  periods,  that 
they  will  attain  together,  in  a  universal  uniformity,  an 
eternal  repose. 

We  shall  see  that  metallic  alloys  undergo  con- 
tinual physical  and  chemical  changes.  They  are 
always  seeking  a  more  or  less  elusive  equilibrium. 
Physicists  in  modern  times  have  given  their  attention 

18 


264  LIFE   AND   DEATH. 

to  this  internal  activity  of  material  bodies,  to  the 
pursuit  of  stability.  Wiedemann,  Warburg,  Tomlin- 
son,  MM.  Duguet,  Brillouin,  Duhem,  and  Bouasse 
have  revived  the  old  experimental  researches  of 
Coulomb  and  Wertheim  on  the  elasticity  of  bodies, 
the  effects  of  pressures  and  thrusts,  the  hammering, 
tempering,  and  annealing  of  metals. 

The  internal  activity  manifested  under  these  cir- 
cumstances presents  quite  remarkable  characteristics 
which  cannot  but  be  compared  to  the  analogous 
phenomena  presented  by  living  bodies.  Thus  have 
arisen  even  in  physics,  a  figurative  terminology,  and 
metaphorical  expressions  borrowed  from  biology. 

Comparison  of  the  Activity  of  Particles  with  Vital 
Activity. — Since  Lord  Kelvin  first  spoke  of  the  fatigue 
of  metals,  or  the  fatigue  of  elasticity,  Bose  has 
shown  in  these  same  bodies  the  fatigue  of  electrical 
contact.  The  term  accommodation  has  been  employed 
in  the  study  of  torsion,  and  according  to  Tomlinson 
for  the  very  phenomena  which  are  the  inverse  of 
those  of  fatigue.  The  phenomena  presented  by  glass 
when  acted  on  by  an  external  force  which  slowly 
bends  it,  have  been  called  facts  of  adaptation.  The 
manner  in  which  a  bar  of  steel  resists  wire-drawing 
has  been  compared  to  defensive  processes  against 
threatened  rupture.  And  M.  C.  E.  Guillaume  speaks 
somewhere  of  "  the  heroic  resistance  of  the  bar  of 
nickel-steel."  The  term  "defence"  has  also  been 
applied  to  the  behaviour  of  chloride  or  iodide  of 
silver  when  exposed  to  light. 

There  has  been  no  hesitation  in  using  the  term 
"  memory "  concurrently  with  that  of  hysteresis  to 
designate  the  behaviour  of  bodies  acted  on  by 
magnetism  or  by  certain  mechanical  forces.  It  is 


EVOLUTION   AND   MUTABILITY   OF   MATTER.     265 

true  that  M.  H.  Bouasse  protests  in  the  name  of  the 
physico-mathematicians  against  the  employment  of 
these  figurative  expressions.  But  has  he  not  himself 
written  "  a  twisted  wire  is  a  wound-up  watch,"  and 
elsewhere,  "  the  properties  of  bodies  depend  at  every 
moment  upon  all  anterior  modifications  "  ?  Does  not 
this  imply  that  they  retain  in  some  manner  the 
impression  of  their  past  evolution  ?  Powerful  de- 
formative  agencies  leave  a  trace  of  their  action  ;  they 
modify  the  body's  condition  of  molecular  aggregation, 
and  some  physicists  go  so  far  as  to  say  that  they  even 
modify  its  chemical  constitution.  With  the  exception 
of  M.  Duhem,  the  disciples  of  the  mechanical  school 
who  have  studied  elasticity  admit  that  the  effect  of  an 
external  force  upon  a  body  depends  upon  the  forces 
which  have  been  previously  acting  on  it,  and  not 
merely  upon  those  which  are  acting  on  it  at  the 
present  moment.  Its  present  state  cannot  be  antici- 
pated, it  is  the  recapitulation  of  preceding  states. 
The  effect  of  a  torsional  force  upon  a  new  wire  will 
be  different  from  that  of  the  same  force  upon  a  wire 
previously  subjected  to  torsions  and  detorsions.  It 
was  with  reference  to  actions  of  this  kind  that 
Boltzmann,  in  1876,  declared  that  "a  wire  that  has 
been  twisted  or  drawn  out  remembers  for  a  certain 
time  the  deformations  which  it  has  undergone." 
This  memory  is  obliterated  and  disappears  after  a 
certain  definite  period.  Here  then,  in  a  problem  of 
static  equilibrium,  we  find  introduced  an  unexpected 
factor — time. 

To  sum  up,  it  is  the  physicists  themselves  who 
have  indicated  the  correspondence  between  the  con- 
dition of  existence  in  many  brute  bodies  and  that  in 
many  living  bodies.  It  cannot  be  expected  that 


266  LIFE    AND    DEATH. 

these  analogies  will  in  any  way  serve  as  explanations. 
We  should  rather  seek  to  derive  the  vital  from  the 
physical  phenomenon.  This  is  the  sole  ambition  of 
the  physiologist.  To  derive  the  physical  from  the 
vital  phenomenon  would  be  unreasonable.  We  do 
not  attempt  to  do  this  here.  It  is  nevertheless  true 
that  analogies  are  of  service,  were  it  only  to  shake  the 
support  which,  from  the  time  of  Aristotle,  has  been 
accorded  to  the  division  of  the  bodies  of  nature  into 
psuchia  and  apsucliia — i.e.,  into  living  and  brute 
bodies. 

§  2.  THE  BROWNIAN  MOVEMENT. 

The  Existence  of  the  Brownian  Movement. — The 
simplest  way  of  judging  of  the  working  activity  of 
matter  is  to  observe  it  when  the  liberty  of  the 
particles  is  not  interfered  with  by  the  action  of  the 
neighbouring  particles.  We  approximate  to  this 
condition  when  we  watch,  through  the  microscope, 
grains  of  dust  suspended  in  a  liquid,  or  globules  of 
oil  suspended  in  water.  Now  what  we  see  is  well 
known  to  all  microscopists.  If  the  granulations  are 
sufficiently  small,  they  seem  to  be  never  at  rest. 
They  are  animated  by  a  kind  of  incessant  tremor  ; 
we  see  the  phenomena  called  the  "  Brownian  move- 
ment." This  movement  has  struck  all  observers  since 
the  invention  of  the  magnifying  glass  or  simple 
microscope.  But  the  English  botanist,  Brown,  in 
1827,  made  it  the  object  of  special  research  and  gave 
it  his  name.  The  exact  explanation  of  it  remained 
for  a  long  time  obscure.  It  was  given  in  1894  by 
M.  Gouy,  the  learned  physicist  of  the  Faculty  of 
Lyons. 


EVOLUTION    AND    MUTABILITY    OF    MATTER.     267 

The  observer  who  for  the  first  time  looks  through 
the  microscope  at  a  drop  of  water  from  the  river,  from 
the  sea,  or  from  any  ordinary  source — that  is  to  say, 
water  not  specially  purified — is  struck  with  surprise 
and  admiration  at  the  motion  revealed  to  him. 
Infusoria,  microscopic  articulata,  and  various  micro- 
organisms people  the  microscopic  field,  and  animate 
it  by  their  movements  ;  but  at  the  same  time  all  sorts 
of  particles  are  also  agitated,  particles  which  cannot 
be  considered  as  living  beings,  and  which  are,  in  fact, 
nothing  but  organic  detritus,  mineral  dust,  and  debris 
of  every  description.  Very  often  the  singular  move- 
ments of  these  granulations,  which  simulate  up  to  a 
certain  point  those  of  living  beings,  have  perplexed 
the  observer  or  led  him  to  erroneous  conclusions,  and 
the  bodies  have  been  taken  for  animalcules  or  for 
bacteria, 

Cliaracters  of  this  Movement. — But  it  is  as  a  rule 
quite  easy  to  avoid  this  confusion.  The  Brownian 
movement  is  a  kind  of  oscillation,  a  stationary, 
dancing  to-and-fro  movement  It  is  a  Saint  Vitus's 
dance  on  one  and  the  same  spot,  and  is  thus  dis- 
tinguished from  the  movements  of  displacement 
customary  with  animate  beings.  Each  particle  has 
its  own  special  dance.  Each  one  acts  on  its  own 
account,  independently  of  its  neighbour.  There  is, 
however,  in  the  execution  of  these  individual  oscilla- 
tions a  kind  of  common  and  regular  character  which 
arises  from  the  fact  that  their  amplitudes  differ 
little  from  each  other.  The  largest  particles  are 
the  slowest ;  when  above  four  thousandths  of  a 
millimetre  in  diameter,  they  almost  cease  to  be 
mobile  The  smallest  are  the  most  active.  When  so 
small  as  to  be  barely  visible  in  the  microscope,  the 


268  LIFE   AND   DEATH. 

movement  is  extremely  rapid,  and  can  only  occasion- 
ally be  perceived.  It  is  probable  that  it  would  be 
still  more  accelerated  in  smaller  objects;  but  the  latter 
will  always  escape  our  observation. 

Its  Independence  of  the  Nature  of  the  Bodies  and  of  the 
Environment, — M.  Gouy  remarked  that  the  move- 
ment depends  neither  on  the  nature  nor  on  the  form 
of  the  particles.  Even  the  nature  of  the  liquid  has 
but  little  effect.  Its  degree  of  viscosity  alone  comes 
into  play.  The  movements  are,  indeed,  more  lively 
in  alcohol  or  ether,  which  are  very  mobile  liquids ; 
they  are  slow  in  sulphuric  acid  and  in  glycerine.  In 
water,  a  grain  one  two-thousandth  of  a  millimetre  in 
diameter  traverses,  in  a  second,  ten  or  twelve  times  its 
own  length. 

The  fact  that  the  Brownian  movement  is  seen  in 
liquors  which  have  been  boiled,  in  acids  and  in 
concentrated  alkalies,  in  toxic  solutions  of  all  degrees 
of  temperature,  shows  conclusively  that  the  pheno- 
menon has  no  vital  significance ;  that  it  is  in  no  way 
connected  with  vital  activity  so  called. 

Its  Indefinite  Duration. — The  most  remarkable  char- 
acter of  this  phenomenon  is  its  permanence,  its 
indefinite  duration.  The  movement  never  ceases, 
the  particles  never  attain  repose  and  equilibrium. 
Granitic  rocks  contain  quartz  crystals  which,  at  the 
moment  of  their  formation,  include  within  a  closed 
cavity  a  drop  of  water  containing  a  bubble  of  gas. 
These  bubbles,  contemporary  with  the  Plutonian  age 
of  the  globe,  have  never  since  their  formation  ceased 
to  manifest  the  Brownian  movement. 

Its  Independence  of  External  Conditions. — What  is 
the  cause  of  this  eternal  oscillation  ?  Is  it  a  tremor 
of  the  earth  ?  No !  M.  Gouy  saw  the  Brownian 


EVOLCTTOH  AXD  MUTABILITY  OF  MATTER.    269 

movement  far  away  from  cities;  where  the  mercurial 
mirror  of  a  seismoscope  showed  no  subterranean 
vibration.  It  does  not  increase  when  the  violations 
occur  and  become  quite  appreciable.  Neither  is  it 
changed  by  variation  in  light,  magnetism,  or  electric 
influences;  in  a  word,  by  any  external  occurrences. 
The  result  of  observation  is  to  place  before  us  the 
paradox  of  a  phenomenon  which  is  kept  up  and 
indefinitely  perpetuated  in  the  interior  of  a  body 
without  known  external  cause. 

TJu  Srvsnriam  Mmxm&U  must  be  the  first  Stage  of 
Molecular  Motion, — When  we  take  in  our  hands  a 
sheet  of  quartz  containing  a  gaseous  inclusion,  we 
seem  to  be  holding  a  perfectly  inert  object.  When 
we  have  placed  it  upon  the  stage  of  the  microscope, 
and  have  seen  the  agitation  of  the  bubble,  we  are 
convinced  that  this  seeming  inertia  is  merely  an 
illusion. 

Repose  exists  only  because  of  our  limited  vision. 
We  see  the  objects  as  we  see  from  alar  a  crowd  of 
people.  We  perceive  them  only  as  a  whole,  without 
being  able  to  discern  the  individuals  or  their  move- 
ments. A  visible  object  is,  in  the  same  way,  a  mass 
of  particles.  It  is  a  molecular  crowd.  It  gives  us 
the  impression  of  an  indivisible  mass,  of  a  block  in 
repose. 

But  as  soon  as  the  lens  brings  us  near  to  this 
crowd,  as  soon  as  the  microscope  enlarges  for  us  the 
minute  elements  of  the  brute  body,  then  they  appear 
to  us,  and  we  perceive  the  continual  agitation  of  those 
elements  which  are  less  than  four  thousandths  of  a 
millimetre  in  diameter.  The  smaller  the  particles 
under  consideration,  the  more  lively  are  their  move- 
ments. From  this  we  infer  that  if  we  could  perceive 


270  LIFE    AND    DEATH. 

molecules,  whose  probable  dimensions  are  about  one 
thousand  times  less,  their  probable  velocity  would  be, 
as  required  by  the  kinetic  theory,  some  hundreds  of 
metres  per  second.  In  the  case  of  objects  we  can 
only  just  see,  the  Brownian  velocity  is  only  a  few 
thousandths  of  a  millimetre  per  second.  No  doubt, 
concludes  M.  Gouy,  the  particles  that  show  this 
velocity  are  really  enormous  when  compared  with 
true  molecules.  From  this  point  of  view  the 
Brownian  movement  is  but  the  first  degree,  and  a 
magnified  picture  of  the  molecular  vibrations  assumed 
in  the  kinetic  theory. 

§  3.  THE  INTERNAL  ACTIVITY  OF  BODIES. 

Migration  of  Material  Particles. —  In  the  Brownian 
movement  we  take  into  account  only  very  small, 
isolated  masses,  small  free  fragments — i.e.,  material 
particles  which  are  not  hampered  by  their  relations  to 
neighbouring  particles.  Any  one  but  a  physicist 
might  believe  that  in  true  solids  endowed  with 
cohesion  and  tenacity,  in  which  the  molecules  were 
bound  one  to  the  other,  in  which  form  and  volume 
are  fixed,  there  could  be  no  longer  movements  or 
changes.  This  is  a  mistake.  Physics  teaches  us  the 
contrary,  and,  in  late  years  especially,  has  furnished 
us  characteristic  examples.  There  are  real  migrations 
of  material  particles  throughout  solid  bodies — migra- 
tions of  considerable  extent.  They  are  accomplished 
through  the  agency  of  diverse  forces  acting  externally 
— pressures,  thrusts,  torsions;  sometimes  under  the 
action  of  light,  sometimes  under  the  action  of  elec- 
tricity, sometimes  under  the  influence  of  forces  of 


EVOLUTION  AND   MUTABILITY  OF   MATTER-     271 

diffusion.  The  microscopic  observation  of  alloys  by 
H.  and  A.  Lechatelier,  J.  Hopkinson,  Osmond,  Charpy, 
J.  R.  Benoit;  researches  into  their  physical  and 
chemical  properties  by  Calvert,  Matthiessen,  Riche, 
Roberts  Austen,  Lodge,  Laurie,  and  C  E.  Guillaume ; 
experiments  on  the  electrolysis  of  glass,  and  the 
curious  results  of  Bose  upon  electrical  contact  of 
metals,  show  in  a  striking  manner  the  chemical  and 
kinetic  evolutions  which  occur  in  the  interior  of 
bodies. 

Migration  under  tJu  Action  of  Wright. — An  ex- 
periment by  Obermeyer,  dating  from  1877,  furnishes 
a  good  example  of  the  motions  of  solid  bodies 
through  a  hardened  viscid  mass,  taking  place  under 
the  influence  of  weight.  The  black  wax  that 
shoemakers  and  boatbuilders  use,  is  a  kind  of  resin 
extracted  from  the  pine  and  other  resinous  trees, 
melted  in  water,  and  separated  from  the  more  fluid 
part  which  rises  from  it.  Its  colour  is  due  to  the 
lampblack  produced  by  the  combustion  of  straw  and 
fragments  of  bark.  At  an  ordinary  temperature  it  is 
a  mass  so  hard  that  it  cannot  always  be  easily 
scratched  by  the  finger-nail ;  but  if  it  is  left  to  itself 
in  a  receptacle,  it  finally  yields,  spreads  out  as  if  it 
were  a  liquid,  and  conforms  to  the  shape  of  the  vessel. 
Suppose  we  place  within  a  cavity  hollowed  out  of  a 
piece  of  wood  a  portion  of  this  substance,  and  keep  it 
there  by  means  of  a  few  pebbles,  having  previously 
placed  at  the  bottom  of  the  cavity  a  few  fragments  of 
some  light  substance,  such  as  cork.  The  piece  of  wax 
is  thus  between  a  light  body  below  and  a  heavy  body 
above.  If  we  wait  a  few  days,  this  order  is  reversed 
—the  wax  has  filled  the  cavity  by  conforming  to  it; 
the  cork  has  passed  through  the  wax  and  appears  on 


272  LIFE    AND    DEATH. 

the  surface,  while  the  stones  are  at  the  bottom.  We 
have  here  the  celebrated  experiment  of  the  flask  with 
the  three  elements,  in  which  are  seen  the  liquids 
mercury,  oil,  and  water  superposed  in  the  order  of 
their  density,  but  in  this  case  demonstrated  with 
solid  bodies. 

Influence  of  Diffusion. — Diffusion,  which  dissemin- 
ates liquids  throughout  each  other,  may  also  cause 
solids  to  pass  through  other  solids.  Of  this  W. 
Roberts  Austen  gave  a  convincing  proof.  This  in- 
genious physicist  placed  a  little  cylinder  of  lead  upon 
a  disc  of  gold,  and  kept  the  whole  at  the  temperature 
of  boiling  water.  At  this  temperature  both  metals 
are  perfectly  solid,  for  the  melting  point  of  gold  is 
1, 200°  C,  and  of  lead  is  330°.  Still,  after  this  contact 
has  been  prolonged  for  a  month  and  a  half,  analysis 
shows  that  the  gold  has  become  diffused  through  the 
top  of  the  cylinder  of  lead. 

Influence  of  Rlectrolysis. — Electrolysis  offers  another 
no  less  remarkable  means  of  transportation.  By  its 
means  we  may  force  metals,  such  as  sodium  or  lithium, 
through  glass  walls.  The  experiment  may  be  per- 
formed as  indicated  by  M.  Charles  Guillaume.  A 
glass  bulb  containing  mercury  is  placed  in  a  bath  of 
sodium  amalgam,  and  a  current  is  then  made  to  pass 
from  within  outward.  After  some  time  it  can  be 
shown  that  the  metal  has  penetrated  the  wall  of  the 
bulb,  and  has  become  dissolved  within  it. 

Influence  of  Mechanical  Pressure, — Mechanical  pres- 
sure is  also  capable  of  causing  one  metal  to  pass  into 
another.  We  need  not  recall  the  well-known  experi- 
ment of  Cailletet,  who,  by  employing  considerable 
pressure,  caused  mercury  to  sweat  through  a  block  of 
iron,  In  a  more  simple  manner  W.  Spring  showed 


EVOLUTION    AND    MUTABILITY   OF    MATTER.     273 

that  a  disc  of  copper  could  be  welded  to  a  disc  of  tin 
by  pressing  them  strongly  one  against  the  other.  Up 
to  a  certain  distance  from  the  surfaces  of  contact 
a  real  alloy  is  formed;  a  layer  of  bronze  of  a  certain 
thickness  unites  the  two  metals,  and  this  could  not 
take  place  did  not  the  particles  of  both  metals 
mutually  interpenetrate. 

§  4.  INTERNAL  ACTIVITY  OF  ALLOYS. 

Structure  of  Alloys. — Metallic  alloys  have  a  re- 
markable structure,  which  is  essentially  mobile,  and 
which  we  have  only  now  begun  to  understand  by  the 
aid  of  the  microscope.  Microscopical  examination 
justifies  to  a  certain  degree  Coulomb's  conjecture. 
That  illustrious  physicist  explained  the  physical  pro- 
perties of  metals  by  imagining  them  to  be  formed  of 
two  kinds  of  elements — integral  particles,  to  which  the 
metal  owes  its  elastic  properties,  and  a  cement  which 
binds  the  particles,  and  to  which  it  owes  its  coherence. 
M.  Brillouin  has  also  taken  up  this  hypothesis  of 
duality  of  structure.  The  metal  is  supposed  to  be 
formed  of  very  small,  isolated,  crystalline  grains, 
embedded  in  an  almost  continuous  network  of  viscous 
matter.  A  more  or  less  compact  mass  surrounding 
more  or  less  distinct  crystals  is  the  conception  which 
may  be  formed  of  an  alloy. 

Changes  of  Structure  produced  by  Deforming 
Agencies. — It  has  been  shown  that  profound  changes 
of  crystalline  structure  can  be  produced  by  various 
mechanical  means,  such  as  hammering,  and  the 
stretching  of  metallic  bars  carried  to  the  point  of 
rupture.  Some  of  these  changes  are  very  slow,  and 
it  is  only  after  months  and  years  that  they  are  com- 


274  LIFE    AND   DEATH. 

pleted,  and  the  metal  attains  the  definite  equilibrium 
corresponding  to  the  conditions  to  which  it  is  exposed. 
Though  there  may  be  discussions  concerning  the 
extent  of  the  transformations  to  which  it  is  subjected, 
though  some  believe  they  affect  the  chemical  con- 
dition of  the  alloy,  while  others  limit  its  power  to 
physical  effects,  it  is  nevertheless  true — and  this 
brings  us  back  to  our  subject — that  the  mass  of  these 
metals  is  at  work,  and  that  it  only  slowly  attains  the 
phase  of  complete  repose. 

TJie  Slow  Re-establishment  of  Equilibrium.  Re- 
sidual Effect. — These  operations  by  which  the  physical 
characters  of  metals  are  changed,  and  by  which  they 
are  adapted  to  a  variety  of  industrial  needs — com- 
pression, hammering,  rolling,  stretching,  and  torsion — 
have  an  immediate,  very  apparent  effect;  but  they 
have  also  a  consecutive  effect,  slowly  produced,  much 
less  marked  and  less  evident.  This  is  the  "  residual 
effect,"  or  "  Nachwirkung"  of  the  Germans.  It  is  not 
without  importance,  even  in  practical  applications. 

Heat  also  creates  a  kind  of  forced  equilibrium. 
This  becomes  but  slowly  modified,  so  that  a  body 
may  remain  for  a  long  time  in  a  state  which  is,  how- 
ever, not  the  most  stable  for  the  conditions  under 
which  it  is  considered.  The  number  of  these  bodies 
not  in  equilibrium  is  as  great  as  that  of  the  substances 
which  have  been  exposed  to  fusion.  All  the  Plutonic 
rocks  are  in  this  condition.  Glass  presents  a  con- 
dition of  the  same  kind.  Thermometers  placed  in 
melting  ice  do  not  always  mark  the  zero  Centigrade. 
This  displacement  of  the  zero  point  falsifies  all 
records  if  care  is  not  taken  to  correct  it.  The 
correction  usually  requires  prolonged  observation. 
The  theory  of  the  displacement  of  the  thermometric 


EVOLUTION   AND    MUTABILITY   OF    MATTER.    2J5 

zero  is  not  entirely  established ;  but  we  may  suppose, 
with  the  author  of  the  Traite  de  T/urmomctrie,  that  in 
glass,  as  in  alloys,  are  to  be  found  compounds  which 
vary  according  to  the  temperature.  At  each  tem- 
perature glass  tends  to  assume  a  determinate  com- 
position and  a  corresponding  state  of  equilibrium ; 
but  the  previous  temperature  to  which  it  has  been 
subjected  clearly  has  an  influence  on  the  rapidity 
with  which  it  attains  its  state  of  repose.  The  effect 
of  variation  is  more  marked  when  we  observe,  glass  ot 
more  complicated  composition.  We  can  understand 
that  those  which  contain  comparable  quantities  of  the 
two  alkalies,  soda  and  potash,  may  be  more  subject 
to  these  modifications  than  those  having  a  more 
simple  composition  based  on  a  single  alkali. 

Effects  of  Annealing. — A  piece  of  brass  wire  that 
has  been  drawn  and  then  heated  is  the  scene  of 
certain  very  remarkable  internal  changes,  and  these 
have  been  only  recently  recognized.  The  violent 
treatment  of  the  metallic  thread  in  forcing  it  through 
the  hole  -in  the  die  has  crushed  the  crystalline 
particles;  the  interior  state  of  the  wire  is  that  of 
broken  crystals  embedded  in  a  granular  mass. 
Heating  changes  all  that  The  crystals  separate, 
repair  themselves,  and  are  built  up  again;  they  are 
then  hard,  geometrical  bodies,  in  an  amorphous, 
relatively  soft  and  plastic  mass;  their  number  keeps 
on  increasing;  equilibrium  is  not  established  until  the 
entire  mass  is  crystallized.  We  may  imagine  how 
many  displacements,  enormous  when  compared  with 
their  dimensions,  the  molecules  have  to  undergo  when 
passing  through  the  resisting  mass,  and  arranging 
themselves  in  definite  places  in  the  crystalline 
structures. 


276  LIFE    AND    DEATH. 

in  the  same  way,  too,  in  the  manufacture  of  steel, 
the  particles  of  coal  at  first  applied  to  the  surface 
pass  through  the  iron. 

This  faculty  of  molecular  displacement  enables  the 
metal  in  some  cases  to  modify  its  state  at  one  point 
or  another.  The  use  made  of  this  faculty  under 
certain  circumstances  is  very  curious,  greatly  re- 
sembling the  adaptation  of  an  animal  to  its  environ- 
ment, or  the  methods  of  defence  against  agents  that 
might  destroy  it. 

Effect  of  Stre telling.  Hartmann's  Experiment. — 
When  a  cylindrical  rod  of  metal,  held  firmly  at  either 
end — a  test-piece,  as  it  is  called  in  metallurgy — is 
pulled  sufficiently  hard,  it  often  elongates  consider- 
ably, part  of  the  elongation  disappearing  as  soon  as 
the  strain  ceases,  and  the  other  part  remaining.  The 
total  elongation  is  thus  the  sum  of  an  "  elastic 
elongation,"  which  is  temporary,  and  a  "  permanent 
elongation."  If  we  continue  the  stretching,  there 
appears  at  some  point  of  the  rod  a  local  extension 
with  contraction  of  sectional  area.  It  is  here  that  the 
rod  will  break. 

But  in  place  of  continuing  the  stretching,  Mr. 
Hartmann  suspends  it.  He  stops,  as  if  to  give  the 
"metal-being"  time  to  rally.  During  this  delay  it 
would  seem  that  the  molecules  hasten  to  the  menaced 
point  to  reinforce  and  harden  the  weak  part.  In 
fact  the  metal,  which  was  soft  at  other  points,  at 
this  spot  looks  like  tempered  metal.  It  is  no  longer 
extensible. 

When  the  experimenter  begins  the  stretching  again 
after  this  rest,  and  after  the  narrowed  bar  has  been 
rolled  and  become  cylindrical  again,  the  local  ex- 
tension and  sectional  contraction  is  forced  to  occur  at 


EVOLUTION    AND    MUTABILITY   OF   MATTER.    2J7 

another  point.     If  another  rest  is  given  at  this  point 
the  metal  will  also  become  hardened. 

If  we  repeat  the  experiment  a  sufficient  number  of 
times,  we  shall  find  a  total  transformation  of  the  rod, 
which  becomes  hardened  throughout  its  entire  extent. 
It  will  break  rather  than  elongate  if  the  stretching  is 
sufficiently  severe. 

Nickel  Steels — their  "Heroic'"'  Resistance. — Nickel 
steels  present  this  phenomena  in  an  exaggerated 
degree.  The  alternation  of  operations  which  we 
have  just  described,  bringing  the  various  parts  of  an 
ordinary  steel  rod  into  a  tempered  state,  is  not 
necessary  with  nickel  steel.  The  effect  is  produced 
in  the  course  of  a  single  trial.  As  soon  as  there  is 
any  tendency  to  contraction  the  alloy  hardens  at  that 
precise  place ;  the  contraction  is  hardly  noticeable  ; 
the  movement  is  stopped  at  this  point  to  attack 
another  weak  point,  stops  there  again  and  attacks  a 
third,  and  so  on  ;  and,  finally,  the  paradoxical  fact 
appears  that  a  rod  of  metal  which  was  in  a  soft  state 
and  could  be  considerably  elongated  has  now  become 
throughout  its  whole  extent  as  hard,  brittle,  and 
inextensible  as  tempered  steel.  It  is  in  connection 
with  this  point  that  M.  C.  E.  Guillaume  spoke  of 
'•  heroic  resistance  to  rupture."  It  would  seem,  in 
fact,  as  if  the  ferro-nickel  bar  had  reinforced  each 
weak  point  as  it  was  threatened.  It  is  only  at  the 
end  of  these  efforts  that  the  inevitable  catastrophe 
occurs. 

Effect  of  Temperature.  —  When  the  temperature 
changes,  it  is  seen  that  these  ferro-nickel  bars  elongate 
or  retract,  modifying  at  the  same  time  their  chemical 
constitution.  But  these  effects,  like  those  which  occur 
in  the  glass  bulb  of  a  thermometer,  do  not  occur 


278  LIFE   AND    DEATH. 

at  once.  They  are  produced  rapidly  for  one  part,  and 
more  slowly  for  a  small  remaining  portion.  Bars  of 
ferro-nickel  which  have  been  kept  at  the  same 
temperature  change  gradually  in  length  in  the  course 
of  a  year.  Can  we  find  a  better  proof  of  internal 
activity  occurring  in  a  substance  differing  so  greatly 
from  living  matter? 

Nature  of  the  Activity  of  Particles. — These  are 
examples  of  the  internal  activity  that  occurs  in  brute 
bodies.  Besides,  these  facts  that  we  are  quoting 
merely  to  refute  Bichat's  assertion  relative  to  the 
immutability  of  brute  bodies,  and  to  show  us  their 
activity,  also  afford  us  another  proof.  They  show 
that  this  activity,  like  that  of  animals,  wards  off 
foreign  intervention,  and  that  this  parrying  of  the 
attack,  again  like  that  of  animals,  is  adapted  for  the 
defence  and  preservation  of  the  brute  mass.  So  that 
if  we  consider  of  special  importance  the  adaptative, 
teleological  characteristic  of  vital  phenomena,  a 
characteristic  which  is  so  easily  made  too  much  of 
in  biological  interpretations,  we  may  also  find  it 
again  in  the  inanimate  world.  To  this  end  we  may 
add  to  the  preceding  examples  one  more  which  is 
no  less  remarkable.  This  is  the  famous  case  of 
Becquerel's  process  for  colour-photography. 

Colour-PhotograpJiy. — A  greyish  plate,  treated  with 
chloride  or  iodide  of  silver  and  exposed  to  a  red  light, 
rapidly  becomes  red.  It  is  then  exposed  to  green 
light,  and  after  passing  through  dull  and  obscure 
tints  it  becomes  green.  To  explain  this  remarkable 
phenomenon,  we  cannot  improve  on  the  following 
statement: — The  silver  salt  protects  itself  against 
the  light  that  threatens  its  existence  ;  that  light 
causes  it  to  pass  through  all  kinds  of  stages  of 


EVOLUTION   AND   MUTABILITY   OF   MATTER.    279 

coloration  before  reducing  it ;  the  salt  stops  at  the 
stage  which  protects  it  best  It  stops  at  red,  if  it  is 
red  light  that  assails  it,  because  in  becoming  red  by 
reflection  it  best  repels  that  light — i.e.,  it  absorbs  it 
the  least 

It  may  then  be  advantageous,  for  the  compre- 
hension of  natural  phenomena,  to  regard  the  trans- 
formation of  inanimate  matter  as  manifestations  of  a 
kind  of  internal  life. 

Conclusion.  Relations  of  the  Surrounding  Medium 
to  the  Living  Being  and  the  Brute  Body.  —  Brute 
bodies,  then,  are  not  immutable  any  more  than  are 
living  bodies.  Both  depend  on  the  medium  that 
surrounds  them,  and  they  depend  upon  it  in  the 
same  way.  Life  brings  together,  brings  into  conflict, 
an  appropriate  organism  and  a  suitable  environment. 
Auguste  Comte  and  Claude  Bernard  have  taught 
us  that  vital  phenomena  result  from  the  reciprocal 
action  of  these  two  factors  which  are  in  close  corre- 
lation. It  is  also  from  the  reciprocal  action  of  the 
environment  and  the  brute  body  that  inevitably 
result  the  phenomena  which  that  body  presents. 
The  living  body  is  sometimes  more  sensitive  to 
variations  of  the  ambient  medium  than  is  the  brute 
body,  but  at  other  times  the  reverse  is  the  case. 
For  example,  there  is  no  living  organism  as  im- 
pressionable to  any  kind  of  stimulus  whatever  as  the 
bolometer  is  to  the  slightest  variations  of  temperature. 

There  can  only  be,  then,  one  chemically  immutable 
body — namely,  the  atom  of  a  simple  body,  since,  by 
its  very  definition,  it  remains  unaltered  and  intangible 
in  combinations.  This  notion  of  an  unalterable  atom 
has,  however,  itself  been  attacked  by  the  doctrine  of 
the  ionization  of  particles  due  to  Sir  J.  J.  Thomson; 

19 


280  LIFE   AND   DEATH. 

and  besides,  with  very  few  exceptions — those  of 
cadmium,  mercury,  and  the  gases  of  the  argon  series 
— the  atoms  of  simple  bodies  cannot  exist  in  a  free 
state. 

Thus,  as  in  the  vital  struggle,  the  ambient  medium 
by  means  of  alimentation  furnishes  to  the  living  being, 
whether  whole  or  fragmentary,  the  materials  of  its 
organization  and  the  energies  which  it  brings  into  play. 
It  also  furnishes  to  brute  bodies  their  materials  and 
their  energies. 

It  is  also  said  that  the  ambient  medium  furnishes 
to  the  living  being  a  third  class  of  things,  the 
stimuli  of  its  activities — i.e.,  its  "provocation  to  action." 
The  protozoon  finds  in  the  aquatic  environment 
which  is  its  habitat  the  stimuli  which  provoke  it  to 
move  and  to  absorb  its  food.  The  cells  of  the 
metazoon  encounter  in  the  same  way  in  the  lymph, 
the  blood,  and  the  interstitial  liquids  which  bathe 
them,  the  shock,  the  stimulus  which  brings  their 
energies  into  play.  They  do  not  derive  from  them- 
selves, by  a  mysterious  spontaneity  without  parallel 
in  the  rest  of  nature,  the  capricious  principle  which 
sets  them  in  motion. 

Vital  spontaneity,  so  readily  accepted  by  persons 
ignorant  of  biology,  is  disproved  by  the  whole  history 
of  the  science.  Every  vital  manifestation  is  a  response 
to  a  stimulus,  a  provoked  phenomenon.  It  is  un- 
necessary to  say  this  i-s  also  the  case  with  brute 
bodies,  since  that  is  precisely  the  foundation  of  the 
great  principle  of  the  inertia  of  matter.  It  is  plain 
that  it  is  also  as  applicable  to  living  as  to  inanimate 
matter. 


CHAPTER  V. 
SPECIFIC  FORM.    LIVING  BODIES  AND  CRYSTALS. 

§  I.  Specific  form  and  chemical  constitution — The  wide  dis- 
tribution of  crystalline  forms — Organization  of  crystals — 
Law  of  relation  between  specific  form  and  chemical 
constitution — Value  of  form  as  a  characteristic  of  brute 
and  living  beings — Parentage,  living  beings  and  mineral 
parentage — Iso-morphism  and  the  faculty  of  cross-breeding 
— Other  analogies.  £  2.  Acquisition  and  re-establishment 
of  the  specific  form— Mutilation  and  regeneration  of  crystals 
— Mechanism  of  reparation. 

§  I.  Specific  Form  and  Clumical  Constitution. — In 
the  enumeration  which  we  have  made  of  the  essential 
features  of  vitality  there  are  three  that  are,  so  to 
speak,  of  the  highest  value.  They  are,  in  the  order  of 
their  importance : — The  possession  of  a  specific  form ; 
the  faculty  of  growth  or  nutrition  :  and  finally,  the 
faculty  of  reproduction  by  generation.  By  restricting 
our  comparison  between  brute  bodies  and  living 
bodies  to  these  truly  fundamental  characters  we 
sensibly  restrict  the  field,  but  we  shall  see  that  it 
does  not  disappear. 

Wide  Distribution  of  Crystalline  Forms.  —  The 
consideration  of  specific  forms  shows  us  that  in 
the  mineral  world  we  need  only  consider  crystallized 
bodies,  as  they  are  almost  the  only  ones  that  possess 
definite  form.  In  restricting  ourselves  to  this  category 
we  do  not  limit  our  field  as  much  as  might  be  sup- 
28l 


282  LIFE   AND   DEATH. 

posed.  Crystalline  forms  are  very  widely  distributed. 
They  are,  in  a  measure,  universal.  Matter  has  a 
decided  tendency  to  assume  these  forms  whenever  the 
physical  forces  which  it  obeys  act  with  order  and 
regularity,  and  when  their  action  is  undisturbed  by 
accidental  occurrences.  In  the  same  way,  too,  living 
forms  are  only  possible  in  regulated  environments, 
under  normal  conditions,  protected  from  cataclysms 
and  convulsions  of  nature. 

The  possession  of  a  specific  form  is  the  most 
significant  feature  of  an  organized  being.  Its 
tendency,  from  the  time  it  begins  to  develop  from 
the  germ,  is  toward  the  acquirement  of  that  form. 
The  progressive  manner  in  which  it  seeks  to  realize 
its  architectural  plan  in  spite  of  the  obstacles  and 
difficulties  that  arise — healing  its  wounds,  repairing 
its  mutilations — all  this,  in  the  eyes  of  the  philo- 
sophical biologist,  forms  what  is  perhaps  the  most 
striking  characteristic  of  a  living  being,  that  which 
best  shows  its  unity  and  its  individuality.  This 
property  of  organogenesis  seems  pre-eminently  the 
vital  property.  It  is  not  so,  however,  for  crystalline 
bodies  possess  it  in  an  almost  equal  degree. 

The  parallel  between  the  crystal  and  a  living  being 
has  been  often  drawn.  I  will  not  reproduce  it  here 
in  detail.  My  sole  desire,  after  sketching  its  principal 
features,  is  to  call  attention  to  the  new  information 
that  has  been  brought  out  by  recent  investigations. 

Organization  of  Crystals.  Vieivs  of  Hatty,  Delafossc, 
Bravais,  and  of  Wallerant. — In  botany,  zoology, 
and  crystallography  we  understand  by  form  an 
assemblage  of  material  constituents  co-ordinated  in 
a  definite  system — i.e.,  the  organization  itself.  The 
body  of  man,  for  example,  is  an  edifice  in  which  sixty 


SPECIFIC   FORM.  ^ 

trillion  cells  ought  each  to  find  its  own  predetermined 
z  '  ~~ : : 

In  crystallography  also  we  understand  by  form  the 
organization  which  crystals  present.  The  grouping 
of  the  elements  of  crystals  is,  perhaps,  more  simple. 
They  are  none  the  less  organized,  in  the  same  sense 
that  living  bodies  are. 

Their  organization,  while  more  uniform  than  that 
of  living  bodies,  still  shows  a  considerable  amount  of 
variation.  It  should  not  be  assumed  that  the  area  of 
a-  crystal  is  completely  filled,  with  contiguous  parts 
applied  one  to  the  other  by  plane  faces,  as  might  be 
supposed  from  the  phenomenon  of  cleavage  which 
dissociates  the  parts  of  the  crystalline  body  into 
solids  of  this  kind.  In  reality,  the  constituent  parts 
are  separated  from  each  other  by  spaces.  They  are 
arranged  in  a  quincunx,  as  Hauy  put  it,  or  along  the 
lines  of  a  network,  to  use  the  terms  of  Delafosse  and 
Bravais.  The  intervals  left  between  them  are  incom- 
parably larger  than  their  diameters.  So  that  in  the 
organization  of  a  crystal  it  is  necessary  to  take  into 
account  two  quite  different  things  : — An  element;  the 
crystalline  particle,  which  is  a  certain  aggregate  of 
chemical  molecules  having  a  determinate  geometrical 
form  ;  and  a  more  or  less  regular,  parallelopipedic  net- 
work, along  the  edges  of  which  are  arranged  in  a  con- 
stant and  definite  manner  the  aforesaid  particles.  The 
external  form  of  the  crystal  indicates  the  existence 
of  the  network.  Its  optical  properties  depend  upon 
the  action  of  the  particles,  as  Wallerant  has  shown : 
Thus  we  must  distinguish  in  a  crystal  between  two 
kinds  of  geometrical  figures — that  of  the  network 
and  that  of  the  particle — and  their  characters  of 
symmetry  may  be  either  concordant  or  discordant 


284  LIFE    AND    DEATH. 

The  crystalline  particle,  the  element  of  the  crystal, 
is  therefore  a  certain  molecular  complex  that  repeats 
itself  identically  and  is  identically  placed  at  the 
nodes  of  the  parallelopipedic  network.  It  has  been 
given  different  names  well  calculated  to  produce 
confusion — the  crystallographic  molecule  of  Mallard, 
the  complex  particle  of  other  authors.  Some  have 
separated  this  element  into  subordinate  elements 
(the  fundamental  particles  of  Wallerant  and  of 
Lapparent). 

These  very  general  outlines  will  suffice  to  show 
how  complex  and  adjustable  is  the  organization  of 
the  crystalline  individual,  which  in  spite  of  its 
geometric  regularity  and  its  rigidity,  may  be  com- 
pared with  the  still  more  flexible  organization  of  the 
living  element.  The  mineral  individual  is  more 
stable,  more  labile — i.e.,  less  prone  to  undergo  change 
than  is  the  living  individual.  We  may  say  with 
M.  Lapparent  that  "  crystallized  matter  presents  the 
most  perfect  and  stable  orderly  arrangement  of 
which  the  particles  of  bodies  are  susceptible." 

Law  of  Relation  of  Specific  Form  to  Chemical 
Constitution. — Crystallization  is  a  method  of  acquiring 
specific  form.  The  geometrical  architecture  of  the 
mineral  individual  is  but  little  less  wonderful  or 
characteristic  than  that  of  the  living  individual.  Its 
form  is  the  result  of  the  mutual  reactions  of  its 
substances  and  of  the  medium  in  which  it  is  pro- 
duced ;  it  is  the  condition  of  material  equilibrium 
corresponding  to  a  given  situation.  This  idea  of  a 
specific  form  belonging  to  a  given  substance  under 
given  conditions  must  be  borne  in  mind.  We  may 
consider  it  as  a  kind  of  principle  of  nature,  an 
elementary  law,  which  may  serve  as  a  point  of 


SPECIFIC   FORM.-  285 

departure  for  the  explanation  of  phenomena.  A 
particular  substance  under  identical  conditions  of 
environment,  must  always  assume  a  certain  form. 

This  close  linking  of  substance  and  form,  admitted 
as  a  postulate  in  physical  sciences,  has  been  carried 
into  biology  by  some  philosophical  naturalists,  by 
M.  Le  Dantec,  for  instance 

Let  us  imitate  them  for  a  moment.  Let  us  cease 
to  seek  in  the  living  being  for  the  prototype  of  the 
crystal ;  let  us,  on  the  contrary,  seek  in  the  crystal  the 
prototype  of  the  living  being.  If  we  succeed  in  this, 
we  shall  then  have  found  the  physical  basis  of  life. 

Let  us  say,  then,  with  the  biologists  we  have 
mentioned,  that  the  substance  of  each  living  being  is 
peculiar  to  it ;  that  it  is  specific,  and  that  its  form — 
that  is  to  say  its  organization — follows  from  it  The 
morphology  of  any  being  whatever,  of  an  animal — 
of  a  setter,  for  example — or  even  of  a  determinate 
being — of  Peter,  of  Paul — is  the  "  crystalline  form  of 
their  living  matter."  It  is  the  only  form  of  equili- 
brium that  can  be  assumed  under  the  given  conditions 
by  the  substance  of  the  setter,  of  Peter,  or  of  Paul, 
just  as  the  cube  is  the  crystalline  form  of  sea-salt 
In  this  manner  these  biologists  have  supposed  that 
they  could  carry  back  the  problem  of  living  form 
to  the  problem  of  living  substance,  and  at  the  same 
time  reduce  the  biological  mystery  to  the  physical 
mystery.  I  have  shown  above  (Chap.  V.  pp.  199-204; 
how  far  this  idea  is  legitimate,  and  how  far  and  with 
what  restrictions  it  may  be  welcomed  and  adopted. 

Value  of  Form  as  a  Characteristic  of  Living  and 
Brute  Beings. — However  this  may  be,  we  may  say, 
without  fear  of  exaggeration,  that  the  crystalline  form 
characterizes  the  mineral  with  no  less  precision  than 


286  LIFE    AND    DEATH. 

the  anatomical  form  characterizes  the  animal  and  the 
plant.  In  both  cases,  form — regarded  as  a  method 
of  distribution  of  the  parts — indicates  the  individual 
and  allows  us  to  diagnose  it  with  more  or  less  facility. 

Parentage  of  Living  Beings  and  Mineral  Parent- 
age.— Still  another  analogy  has  been  noted.  In 
animals  and  plants  similarity  in  form  indicates 
similarity  in  descent,  community  of  origin,  and 
proximity  in  any  scheme  of  classification.  In  the 
same  way  identity  of  crystalline  form  indicates 
mineral  relationship.  Substances  chemically  analo- 
gous show  identical,  geometrically  superposable 
forms,  and  are  thus  arranged  in  family  or  generic 
groups  recognizable  at  a  glance. 

Isomorphism  and  the  Faculty  of  Cross-breeding. — 
And  further,  the  possibility  in  the  case  of  isomorphous 
bodies,  of  their  replacing  each  other  in  the  same  crystal 
during  the  process  of  formation  and  of  thus  mingling, 
so  to  speak,  their  congenital  elements,  may  be 
compared  with  the  possibility  of  inter-breeding  with 
living  beings  of  the  same  species.  Isomorphism  is 
thus  a  kind  of  faculty  of  crossing.  And  as  the 
impossibility  of  crossing  is  the  touchstone  of  taxo- 
nomic  relationship,  testing  it,  and  separating  stocks 
that  ought  to  be  separated,  so  the  operation  of 
crystallization  is  also  a  means  of  separating  from  an 
accidental  mixture  of  mineral  species  the  pure  forms 
which  are  blended  therein.  Crystallization  is  the 
touchstone  of  the  specific  purity  of  minerals  ;  it  is  the 
great  process  in  chemical  purification. 

Other  Analogies. — The  analogies  between  crystal- 
line and  living  forms  have  been  pushed  still  further 
even  to  the  verge  of  exaggeration. 

The  internal  and  external  symmetry  of  animals 


SPECIFIC  POEM.  ::- 

and  plants  has  been  compared  to  that  of  crystals. 
Transitions  or  intergradations  have  been  sought 
between  the  rigid  and  faceted  architecture  of  the 
latter  and  the  flexible  structure  and  curved  surface  of 
the  former;  the ntricolar  form  of  Hovers  of  sulpi""" 
on  the  one  hand,  and  the  geometrical  structure  of  the 
shells  of  radiolarians  on  the  other,  have  shown  a® 
exchange  of  typical  forms  between  the  two  systems. 
An  effort  has  even  been  made  to  draw  a  parallel 
between  six  of  the  principal  types  of  the  animal 
kingdom  and  the  six  crystalline  systems.  If  carried 
as  far  as  th*s,  onr  th*****^  becomes  puerile.  Real 
analogies  will  suffice.  Among  these  the  curious  facts 
of  crystaMicDe  renewal  come  first. 

§2:  CICATRIZATION  ix   LTVTXG  BEINGS  AXD  ix 
CRYSTALS. 

We  know  that  living  beings  not  only  possess  a 
typical  architecture  which  they  have  themselves 
constructed,  bat  that  they  defend  it  against  de- 
structive agencies,  and  that  if  need  arise  they  repair 
it.  The  living  organism  cicatrizes  its  wounds,  repairs 
losses  of  substance,  regenerates  more  or  less  perfectly 
the  parts  that  have  been  removed;  in  other  terms, 
when  it  has  been  mutilated  it  tends  to  reconstruct 
itself  according  to  the  laws  of  its  own  morphology. 
This  phenomenon  of  reconstitution  or  reintegration, 
these  more  or  less  successful  efforts  to  re-establish  its 
form  and  its  integrity,  at  first  appear  to  be  a  char- 
acteristic feature  of  living  beings.  This  is  not  tine 


Mutilation  and  Rc-imt^raticm  cf  Crystals.— Crys- 
tals— let    us    say    crystalline    individuals — show    a 


288  LIFE   AND    DEATH. 

similar  aptitude  for  repairing  their  mutilations. 
Pasteur,  in  an  early  work,  discussed  these  curious 
facts.  Other  experimenters,  Gernez  a  little  later  and 
Rauber  more  recently,  took  up  the  same  subject,  but 
could  do  no  more  than  extend  and  confirm  his 
observations.  Crystals  are  formed  from  a  primitive 
nucleus,  as  the  animal  is  formed  from  an  egg  ;  their 
integral  particles  are  disposed  according  to  efficient 
geometrical  laws,  so  as  to  produce  the  typical  form 
by  a  constructive  process  that  may  be  compared  to 
the  embryogenic  process  which  builds  up  the  body  of 
an  animal.  Now  this  operation  may  be  disturbed  by 
accidents  in  the  surrounding  medium  or  by  the 
deliberate  intervention  of  the  experimenter.  The 
crystal  is  then  mutilated.  Pasteur  saw  that  these 
mutilations  repaired  themselves.  "  When,"  said  he, 
"  a  crystal  from  which  a  piece  has  been  broken  off  is 
replaced  in  the  mother  liquor,  we  see  that  while  it 
increases  in  every  direction  by  a  deposit  of  crystalline 
particles,  activity  occurs  at  the  place  where  it  was 
broken  off  or  deformed ;  and  in  a  few  hours  this 
suffices  not  only  to  build  up  the  regular  amount 
required  for  the  increase  of  all  parts  of  the  crystal, 
but  to  re-establish  regularity  of  form  in  the  mutilated 
part."  In  other  words,  the  work  of  formation  of  the 
crystal  is  carried  on  much  more  actively  at  the  point 
of  lesion  than  it  would  have  been  had  there  been  no 
lesion.  The  same  thing  would  have  occurred  with  a 
living  being. 

Mechanism  of  Reparation. — Gernez  some  years  later 
made  known  the  mechanism  of  this  reparation,  or,  at 
least,  its  immediate  cause.  He  showed  that  on  the 
injured  surface  the  crystal  becomes  less  soluble  than 
on  the  other  facets.  This  is  not,  however,  an  ex- 


SPECIFIC   FORM.  289 

ceptional  phenomenon.  It  is,  on  the  contrary,  quite 
frequently  observed  that  the  different  fares  of  a 
crystal  show  marked  differences  in  solubility*.  This 
is  what  happens  in  every  case  for  the  mutilated  face 
in  comparison  with  the  others;  the  matter  is  less 
soluble  there.  The  consequence  of  this  is  clear ;  the 
growth  must  preponderate  on  that  face,  since  there 
the  mother  liquor  will  become  super-saturated  before 
being  super-saturated  for  the  others.  We  may 
explain  this  result  in  another  way.  Each  face  of  the 
crystal  in  contact  with  the  mother  liquor  is  exposed 
to  two  antagonistic  actions :  The  matter  deposited 
upon  a  surface  may  be  taken  away  and  redissolved  if, 
for  any  reason  whatever,  such  matter  becomes  more 
soluble  than  that  of  the  liquid  stratum  in  contact 
with  it ;  in  the  second  place,  the  matter  of  this  liquid 
stratum  may,  under  contrary  conditions,  be  deposited, 
and  thus  increase  the  body  of  the  crystal.  There  is, 
then,  for  each  point  of  the  crystalline  facet,  a  positive 
operation  of  deposit  which  results  in  a  gain,  and  a 
negative  operation  of  redissolution  which  results  in  a 
loss.  One  or  the  other  effect  predominates  according 
as  the  relative  solubility  is  greater  or  less  for  the 
matter  of  the  facet  under  consideration.  On  the 
mutilated  surface  it  is  diminished,  deposition  then 
prevails. 

But  this  is  only  the  immediate  cause  of  the 
phenomenon ;  and  if  we  wish  to  know  why  the 
solubility  has  diminished  on  the  mutilated  surface 
Ostwald  explains  it  to  us  by  showing  that  crystal- 
lization tends  to  form  a  polyhedron  in  which  the 
surface  energy  is  a  relative  mimimum. 


CHAPTER    VI. 

NUTRITION     IN    THE    LIVING    BEING    AND    IN    THE 
CRYSTAL. 

Assimilation  and  growth  in  the  crystal. — Methods  of  growth 
in  the  crystal  and  in  the  living  being  ;  intussusception  ; 
apposition. — Secondary  and  unimportant  character  of  the 
process  of  intussusception. 

I  HAVE  already  stated  (Chap.  VI.  p.  209)  that  nutrition 
may  be  considered  as  the  most  characteristic  and 
essential  property  of  living  beings.  Such  beings  arc 
in  a  state  of  continual  exchange  with  the  surrounding 
medium.  They  assimilate  and  dissimilate.  By  as- 
similation the  substance  of  their  being  increases  at 
the  expense  of  the  surrounding  alimentary  material, 
which  is  rendered  similar  to  that  of  the  being  itself. 

Assimilation  and  Growth  in  tJie  Crystal, — There 
exists  in  the  crystal  a  property  analogous  to  nutrition, 
a  kind  of  nutrility,  which  is  the  rudiment  of  this 
fundamental  property  of  living  beings.  The  develop- 
ment of  a  crystal  starts  from  a  primitive  nucleus,  the 
germ  of  the  crystalline  individual  that  we  will 
presently  compare  to  the  ovum  or  embryo  of  a  plant 
or  an  animal.  Placed  in  a  suitable  culture-medium — 
i.e.,  in  a  solution  of  the  substance — this  germ 
develops.  It  assimilates  the  matter  in  solution, 
incorporates  the  particles  of  it,  and  increases,  pre- 
serving at  the  same  time  its  form,  reproducing  its 
290 


NUTRITION   IN  THE   LIVING   BEING.  2QI 

specific  type  or  a  variety  of  it  Its  growth  proceeds 
without  interruption.  The  crystalline  individual  may 
attain  quite  a  large  size  if  we  know  how  to  nourish  it 
properly — we  might  say,  to  fatten  it.  Very  fre- 
quently, at  a  given  time,  a  new  particle  of  the  crystal 
serves  in  its  turn  as  a  primitive  nucleus,  and  becomes 
the  point  of  departure  for  a  new  crystal  engrafted 
upon  the  first. 

Taken  from  its  mother  liquor,  placed  where  it 
cannot  be  nourished,  the  crystal,  arrested  in  its 
growth,  falls  into  a  condition  of  rest  not  without 
analogy  to  that  of  a  seed  or  of  a  reviviscent  animal. 
Its  evolution  is  resumed  with  the  return  of  favourable 
conditions — the  bath  of  soluble  matter. 

The  crystal  is  in  a  relation  of  continual  exchange 
with  the  surrounding  medium  which  feeds  it  These 
exchanges  are  regulated  by  the  state  of  this  medium, 
or,  more  exactly,  by  the  state  of  the  liquid  stratum 
which  is  in  immediate  contact  with  the  crystals.  It 
loses  or  it  gains  in  substance  if,  for  example,  this 
layer  becomes  heated  or  cooled  more  rapidly  than  the 
crystal  In  a  general  way,  it  assimilates  ordissimilates 
according  as  its  immediate  environment  is  saturated 
or  diluted.  Here,  then,  we  have  a  kind  of  mobile 
equilibrium,  comparable,  in  some  measure,  to  that  of 
the  living  being. 

MetJiods  of  Growth  of  tJie  Crystal  and  of  the  Living 
Being.  Intussusception.  Apposition. — In  truth,  there 
seems  to  be  a  complete  opposition  between  the  crystal 
and  the  living  being  as  regards  their  manner  of 
nutrition  and  growth.  In  the  one  case  the  method  is 
intussusception ;  in  the  other  it  is  apposition.  The 
crystalline  individual  is  all  surface.  Its  mass  is  im- 
penetrable to  the  nutriti\-e  materials.  Since  only  the 


2Q2  LIFE    AND   DEATH. 

surface  is  accessible,  the  incorporation  of  similar 
particles  is  possible  only  by  external  juxtaposition, 
and  the  edifice  increases  only  because  a  new  layer  of 
stones  has  been  added  to  those  which  were  there 
before.  On  the  contrary,  the  body  of  an  animal  is  a 
mass  essentially  penetrable.  The  cellular  elements 
that  compose  it  have  more  or  less  rounded  and 
flexible  forms.  Their  contact  is  by  no  means  perfect. 
They  have  neither  the  stiffness  nor  the  precision 
of  adjustment  that  the  crystalline  particles  have. 
Liquids  and  gases  can  insinuate  themselves  from 
without  and  circulate  within  the  meshes  of  this  loose 
construction.  Assimilation  can  therefore  take  place 
throughout  its  whole  depth,  and  the  edifice  increases 
because  each  stone  is  itself  increasing. 

The  Secondary  and  Commonplace  Character  of  the 
Process  of  Intussusception, — The  apparent  opposition 
of  these  two  processes  is  doubtless  diminished  if  we 
compare  the  simple  mineral  individual  with  the 
elementary  living  unit,  the  crystalline  particle  with 
the  protoplasmic  mass  of  a  cell.  Without  carrying 
analysis  so  far  as  this,  it  is  yet  easy  to  see  that  appo- 
sition and  intussusception  are  mechanical  means 
that  living  beings  employ  at  one  and  the  same  time 
and  combine  according  to  their  necessities.  The  hard 
parts  of  the  internal  and  external  skeleton  increase 
both  by  interposition  and  superposition,  at  once.  It 
is  by  the  last  method  that  bones  increase  in  diameter, 
and  the  shells  of  molluscs,  the  scales  of  reptiles  and 
fishes,  and  the  testae  of  many  radiate  animals  are 
formed.  In  these  organs,  as  in  crystals,  life  and 
nutrition  occur  at  the  surface. 

Apposition  and  intussusception  are  then  secondary, 
mechanical  arrangements  having  relation  to  the 


NUTRITION   IN   THE   LIVING   BEING.  2Q3 

physical  characters  of  the  body — solidity  in  the 
crystal,  semi-fluidity  in  the  cellular  protoplasm.  If 
we  compare  the  inorganic  liquid  matter  with  the 
semi-fluid  organized  matter,  we  recognize  that  the 
addition  of  substance  takes  place  in  the  same  manner 
in  each — i.e.,  by  interposition.  If  we  add  a  soluble 
salt  to  a  fluid,  the  molecules  of  the  salt  separate 
themselves  and  interpose  themselves  between  those 
of  the  fluid.  There  is,  therefore,  nothing  especially 
mysterious  or  particularly  vital  about  the  process  of 
intussusception.  Applied  to  fluid  protoplasm,  it  is 
merely  the  diffusion  that  ordinarily  occurs  in  mixed 
liquids. 


CHAPTER   VII. 

GENERATION    IN    BRUTE   BODIES   AND   LIVING 
BODIES.      SPONTANEOUS   GENERATION. 

Protoplasm  a  substance  which  continues— Case  of  the  crystal- 
Characteristics  of  generation  in  the  living  being— Property 
.of  growth — Supposed  to  be  confined  to  the  living  being — 
Fertilization  of  micro-organisms—  Fertilization  of  crystals — 
Sterilization  of  crystalline  and  living  media — Spontaneous 
generation  of  crystals  —  Metastable  and  labile  zones  — 
Glycerine  crystals — Possible  extinction  of  a  crystalline 
species — Conclusion. 

WE  have  not  yet  exhausted  the  analogies  between  a 
crystal  and  the  living  being.  The  possession  of  a 
specific  form,  the  tendency  to  re-establish  it  by  re- 
disintegration  and  the  existence  of  a  kind  of  nutrition 
are  not  sufficient  to  constitute  complete  similarity. 
It  still  lacks  a  fundamental  character,  that  of  genera- 
tion. Chauffard  some  time  ago,  in  an  attack  which 
he  made  upon  the  physiological  ideas  of  his  day, 
aptly  exhibited  this  weak  point.  "  Let  us  disregard," 
he  said,  "those  interesting  facts  relative  to  the  acquisi- 
tion of  a  typical  form — facts  that  are  common  to  the 
mineral  world  as  well  as  to  living  beings.  It  is  none 
the  less  true  that  the  crystalline  type  is  in  no  way 
derived  from  other  pre-existing  types,  and  that 
nothing  in  crystallization  recalls  the  actions  ot 
ascendants  and  the  laws  of  heredity." 

This    gap    has    since    been    filled.     The   work    of 
294 


SPONTANEOUS  GENERATION.  2Q5 

Gernez,  of  Vlotette,  of  Lecoq  de  Boisbandran,  the  ex- 
periments of  Ostwald  and  of  Tammann,  the  observa- 
tkxis  of  Crookes  and  of  Armstrong — all  this  series  of 
researches,  so  lucidly  summarized  by  M.  Leo  Errera 
in  his  essays  in  botanical  philosophy,  had  for  their 
result  die  establishment  of  an  unsuspected  relation 
between  the  processes  of  crystallization  and  those  of 
generation  in  animals  and  plants, 

Protoplasm  is  a  Substitute  which  Comtixtus.  The 
Cast  of  the  Crystal. — Under  present  conditions  a  living 
being  of  any  kind  springs  from  another  living  being 
similar  to  Itself. 

Its  protoplasm  is  always  a  continuation  of  the 
protoplasm  of  an  ancestor.  It  is  an  atavic  substance 
of  which  we  do  not  see  the  beginning;  we  only  see  it 
continue.  The  anatomical  element  comes  from  a 
preceding  anatomical  element,  and  the  higher  animal 
itself  comes  from  a  pre-existing  cell  of  the  material 
organism,  the  ovum.  The  ladder  of  filiation  reaches 
back  indefinitely  into  the  past. 

We  shall  see  that  there  is  something  analogous  to 
this  in  certain  crystals.  They  are  born  of  a  preceding 
individual;  they  may  be  considered  as  the  posterity 
of  the  antecedent  crystal  If  we  speak  of  the  matter 
of  a  crystal  as  the  matter  of  a  living  being  is  spoken 
of,  in  cases  of  this  kind  we  would  say  that  the 
crystalline  substance  is  an  atavic  substance  of  which 
we  see  only  the  continuation,  as  in  the  case  of 
protoplasm. 

Characters  of  Gauratitm  in  the  Living  Betmg.^ 
Growth  of  the  living  substance,  and  consequently  of 
the  being  itself,  is  the  fundamental  law  of  vitality. 
Generation  is  the  necessary  consequence  of  growth 
(p.  210} 

20 


296  LIFE    AND    DEATH. 

Living  elements  or  cells  cannot  subsist  indefinitely 
without  increasing  and  multiplying.  The  time  must 
come  when  the  cell  divides,  either  directly  or  in- 
directly; and  then,  instead  of  one  cell,  there  are  two. 
This  is  the  method  of  generation  for  the  anatomical 
element.  In  a  complex  individual  it  is  a  more  or  less 
restricted  part  of  the  organism,  usually  a  simple 
sexual  cell,  that  takes  on  the  formation  of  the  new 
being,  and  assures  the  perpetuity  of  the  protoplasm, 
and  therefore  of  the  species. 

Property  of  Growth.  Its  Supposed  Restriction  to 
Living  Beings. — At  first  it  would  appear  that  nothing 
like  this  occurs  in  inanimate  nature.  The  physical 
machine,  if  we  furnish  it  matter  and  energy,  could  go 
on  working  indefinitely,  without  being  compelled  to 
increase  and  reproduce.  Here,  then,  there  is  an 
entirely  new  condition  peculiar  to  the  organized 
being,  a  property  well'  adapted,  it  would  seem — and 
this  time  without  any  possible  doubt — for  separating 
living  matter  from  brute  matter.  It  is  not  so. 

It  would  not  be  impossible  to  imagine  a  system 
of  chemical  bodies  organized  like  the  animal  or 
vegetable  economy,  so  that  a  destruction  would  be 
compensated  for  by  a  growth.  The  only  thing  im- 
possible is  to  suppose,  with  M.  le  Dantec,  a  destruction 
that  would  at  the  same  time  be  an  analysis.  And  an 
additional  perplexity  occurs  when  he  supposes  that 
in  the  successive  acts  exchanges  of  material  may 
occur. 

There  is  no  necessity  for  making  this  impossible 
chemistry  a  characteristic  of  the  living  being.  The 
chemistry  of  the  living  being  is  general  chemistry. 
Lavoisier  and  Berthelot  enforced  this  view.  We 
should  not  lose  sight  of  the  teachings  of  the  masters. 


SPONTANEOUS   GENERATION.  297 

Let  us  return  to  generation,  properly  so  called,  and 
find  in  it  the  characteristics  of  brute  bodies  and  of 
crystals. 

The  Sowing  of  ^Hero-organisms. — When  a  micro- 
biologist  wishes  to  propagate  a  species  of  micro- 
organisms, he  places  in  a  culture  medium  a  few 
individuals  (one  is  all  that  is  actually  necessary),  and 
soon  observes  their  rapid  multiplication.  Usually,  if 
only  the  ordinary  microbes  in  atmospheric  dust  are 
wanted,  the  operator  need  not  trouble  to  charge  the 
culture;  if  the  culture  tube  remains  open  and  the 
medium  is  suitably  chosen,  some  germ  of  a  common 
species  will  fall  in  and  the  liquid  will  become 
colonized.  This  has  the  appearance  of  spontaneous 
generation. 

T/i£  Sowing  of  Crystals. — Concentrated  solutions  of 
various  substances,  supersaturated  solutions  of  sodium 
magnesium  sulphate,  and  sodium  chlorate  are  also 
wonderful  culture  media  for  certain  mineral  organic 
units — certain  crystalline  germs.  Ch.  Dufour,  ex- 
perimenting with  water  cooled  below  OD  C,  its  point 
of  solidification ;  Ostwald,  with  salol  kept  below  39'.$, 
its  point  of  fusion ;  Tammann,  with  betol,  which 
melts  at  96° ;  and,  before  them,  Gernez,  with  melted 
phosphorus  and  sulphur — all  these  physicists  have 
shown  that  liquids  in  superfusion  are  also  media 
specially  appropriate  for  the  culture  and  propagation 
of  certain  kinds  of  crystalline  individuals. 

Some  of  these  facts  have  become  classic.  Lowitz 
showed  in  1/85  that  a  solution  of  sodium  sulphate 
could  be  concentrated  by  evaporation  so  as  to  contain 
more  salt  than  was  conformable  with  the  temperature, 
without,  however,  depositing  the  excess.  But  if  a 
solid  fragment,  a  crystal  of  salt,  is  thrown  into  the 


298  LIFE    AND    DEATH. 

liquor,  the  whole  of  the  excess  immediately  passes 
into  the  state  of  a  crystallized  mass.  The  first 
crystal  has  engendered  a  second  similar  to  itself; 
the  latter  has  engendered  a  third,  and  so  on  from  one 
to  the  other.  If  we  compare  this  phenomenon  with 
that  of  the  rapid  multiplication  of  a  species  of 
microbes  in  a  suitable  culture  medium,  no  difference 
will  be  perceived.  Or  perhaps  we  may  note  one 
unimportant  difference — the  rapidity  of  the  propaga- 
tion of  the  crystalline  germs  as  opposed  to  the  relative 
slowness  of  the  generation  of  the  micro-organisms. 

Again,  the  propagation  of  crystallization  in  a  super- 
saturated or  superfused  liquid  may  be  delayed  by 
appropriate  devices.  The  crystalline  individual  gives 
birth,  then,  to  another  individual  that  conforms  to  its 
own  type,  or  even  to  varieties  of  that  type  when  such 
exist.  Into  the  right  branch  of  a  U  tube  filled  with 
sulphur  in  a  state  of  superfusion  Gernez  dropped 
octahedric  crystals  of  sulphur,  and  into  the  left  branch 
prismatic  crystals.  On  either  side  were  produced 
new  crystals  conforming  to  the  type  that  had  been 
sown. 

Sterilization  of  Crystalline  Media  and  Living  Media. 
— Ostwald  varied  these  experiments  by  using  salol. 
He  melted  the  substance  by  heating  it  above  39°.  5  C.; 
then,  protecting  it  from  crystals  of  any  kind,  he  let 
the  solution  stand  in  a  closed  tube.  The  salol  re- 
mained liquid  indefinitely — until  it  was  touched  with 
a  platinum  wire  that  had  been  in  contact  with  solid 
salol — i.e.,  until  a  crystalline  germ  was  introduced. 
But  if  the  platinum  wire  has  been  previously  sterilized 
by  passing  it,  as  the  bacteriologists  do,  through  a 
flame,  it  can  then  be  introduced  into  the  liquor  with 
impunity. 


SPONTANEOUS   GENERATION.  299 

The  Dimensions  of  Crystalline  Germs  Compar- 
able te  those  of  Microbes. — We  may  dilute  the  solid 
salol  with  inert  powder — lactin,  for  example — dilute 
the  first  mixture  with  a  second,  the  second  with  a 
third,  and  so  on;  then,  throwing  into  the  solution  of 
surfused  salol  a  tenth  of  a  milligram  from  one  of 
these  various  mixtures,  we  find  that  the  production  of 
crystals  will  not  take  place  if  the  fragment  thrown  in 
weighs  less  than  a  millionth  of  a  milligram,  or 
measures  less  than  ten  thousandths  of  a  millimetre 
in  length.  It  would  seem,  then,  that  these  are  the 
dimensions  of  the  crystalline  particle  or  crystallo- 
graphic  molecule  of  salol.  In  the  same  way  Ostwald 
satisfied  himself  that  the  crystalline  germ  of  hypo- 
sulphite ' of  soda  weighs  about  a  thousand-millionth  of 
a  milligram,  and  measures  a  thousandth  of  a  milli- 
metre; that  of  chlorate  of  soda  weighs  a  ten-millionth 
of  a  milligram.  These  dimensions  are  entirely  com- 
parable with  those  of  microbes. 

All  these  phenomena  have  been  studied  with  a 
detail  into  which  it  is  impossible  to  enter  here,  and 
which  clearly  shows  more  and  more  intimate  analogies 
between  the  formation  of  crystals  and  the  generation 
of  micro-organisms. 

Extension  and  Propagation  of  Crystallization. 
Optimum  Temperature  of  Incubation. — Crystallization 
which  has  commenced  around  a  germ  is  propagated 
more  or  less  rapidly,  and  ends  by  invading  the  whole 
of  the  liquor. 

The  rapidity  of  this  movement  of  extension  depends 
upon  the  conditions  of  the  medium,  especially  upon 
its  temperature.  This  is  shown  very  well  by 
Tammann's  experiments  with  betol.  This  body, 
the  salicylic  ester  of  naphthol,  fuses  at  96°  C.  If  it 


300  LIFE   AND   DEATH. 

is  melted  in  tubes  sealed  at  a  temperature  of  100°  C, 
it  may  be  cooled  to  lower  and  lower  temperatures — 
to  +  70°,  to  +  25°,  to  +  IO°,  to  —  5°  without  solidifying. 
Let  us  suppose  that  by  some  combination  of  circum- 
stances a  few  centres  of  crystallization — that  is  to 
say,  of  crystalline  germs — have  appeared  in  the 
solution.  Solidification  will  extend  slowly  at  the 
ordinary  temperature,  at  20°  to  25°  and  thereabouts. 
On  the  other  hand,  it  will  be  propagated  with  great 
rapidity  if  the  liquor  is  kept  at  about  70°.  This 
point — 70° — is  the  thermal  optimum  for  the  pro- 
pagation of  germs.  It  is  the  most  favourable 
temperature  for  what  may  be  called  their  incubation. 
As  soon  as  the  germs  find  themselves  in  a  liquor  at 
70°  they  increase,  multiply,  and  show  that  they  are  in 
the  best  conditions  for  growth. 

Spontaneous  Generation  of  Crystals.  Optimum 
Temperature  for  the  Appearance  of  Germs. — If  we 
consider  various  supersaturated  solutions  or  liquids 
in  superfusion,  we  shall  soon  discover  that  they  can 
be  arranged  in  two  categories.  Some  remain  in- 
definitely liquid  under  given  conditions  unless  a 
crystalline  germ  is  introduced  into  them.  Others 
solidify  spontaneously  without  artificial  intervention, 
and  such  crystallization  may  even  be  propagated  very 
rapidly  under  determinate  conditions.  This  implies 
that  these  are  conditions  favouring  the  spontaneous 
appearance  of  germs. 

This  distinction  between  substances  of  crystalline 
generation  by  filiation  and  substances  of  spontaneous 
crystalline  generation  is  not  specific.  The  same 
substance  may  present  the  two  methods  of  generation 
according  to  the  conditions  in  which  it  is  placed. 
Betol  furnishes  a  good  example  of  this.  Liquefy  it  at 


SPONTANEOUS   GENERATION.  30! 

TOO'  in  a  sealed  tube  and  keep  it  by  means  of  a  stove 
above  30  ,  and  it  will  remain  liquid  almost  indefinitely. 
On  the  other  hand,  lower  its  temperature  and  leave  it 
for  one  or  two  minutes  at  10",  and  germs  will  appear 
in  the  liquor;  prolong  the  exposure  to  this  degree  of 
heat  and  the  number  of  these  spontaneously  appearing 
germs,  appearing  in  isolation,  will  rapidly  increase. 
On  the  other  hand,  you  will  observe  that  propagation 
by  filiation — that  is  to  say,  by  extension  from  one 
to  another — is  almost  absent.  The  temperature  of 
10°  is  not  favourable  to  that  method  of  generation ; 
and  we  have  just  seen,  in  fact,  that  it  is  at  a  tem- 
perature of  about  70  that  extension  of  crystallization 
from  one  to  another  is  best  accomplished.  The 
temperature  of  70"  was  the  optimum  for  propagation 
by  filiation.  Inversely,  the  temperature  of  10"  is  the 
optimum  for  spontaneous  generation.  Above  and 
below  this  optimum  the  action  is  slower.  \Ve  may 
count  the  centres  of  crystallization,  which  slowly 
extend  further  and  further,  as  in  a  microbic 
culture  one  counts  the  colonies  corresponding  to 
the  germs  primitively  formed.  To  sum  up,  if 
there  is  an  optimum  for  the  formation  of 
crystals,  there  is  a  different  optimum  for  their  rapid 
extension. 

The  Metastable  and Labile  Zones. — This  phenomena 
is  general.  There  is  for  each  substance  a  set  of 
conditions  (temperature,  degree  of  concentration, 
volume  of  the  solution)  in  which  the  crystalline 
individuals  can  be  produced  only  by  germs  or  by 
filiation.  This  is  what  occurs  for  betol  above  the 
temperature  of  30".  The  body  is  then  in  what 
Ostwald-  has  called  a  nietas table  zone.  There  is, 
however,  for  the  same  body  another  set  of  circum- 


3O2  LIFE   AND   DEATH. 

stances  more  or  less  complete,  in  which  its  gems 
appear  simultaneously.  This  is  what  happens  for 
betol  at  about  the  temperatute  of  10°.  These  circum- 
stances are  those  of  the  labile  zone  or  zone  of 
spontaneous  generation. 

Crystals  of  Glycerine. — We  may  go  a  step  further. 
Let  us  suppose,  with  L.  Errera,  that  we  have  a  liquid 
in  a  state  of  metastable  equilibrium,  whose  labile 
equilibrium  is  as  yet  unknown.  This  is  what  actually 
occurs  for  a  very  widely  known  body,  glycerine. 
We  do  not  know  under  what  conditions  glycerine 
crystallizes  spontaneously.  If  we  cool  it,  it  becomes 
viscous  ;  we  cannot  obtain  its  crystals  in  that  way. 
It  was  not  found  in  crystals  until  1867.  In  that 
year,  in  a  cask  sent  from  Vienna  to  London  during 
winter,  crystallised  glycerine  was  found,  and  Crookes 
showed  these  crystals  to  the  Chemical  Society  of 
London.  What  circumstances  had  determined  their 
formation  ?  We  knew  not  then,  and  we  know  not 
now.  It  may  be  observed  that  this  case  of  spon- 
taneous generation  of  the  crystals  of  glycerine  has 
not  remained  the  solitary  instance.  M.  Henninger 
has  noted  the  accidental  formation  of  glycerine 
crystals  in  a  manufactory  in  St.  Denis. 

It  may  be  remarked  that  this  crystalline  species 
appeared,  as  living  species  may  have  done,  at  a  given 
moment  in  an  environment  in  which  a  favourable 
chance  combined  the  necessary  conditions  for  its 
production.  It  is  also  quite  comparable  to  the 
creation  of  a  living  species  ;  for  having  once  appeared 
we  have  been  able  to  perpetuate  it.  The  crystalline 
individuals  of  1867  have  had  a  posterity.  They 
have  been  sown  in  glycerine  in  a  state  of  superfusion, 
and  there  they  reproduced  themselves.  These 


SPONTANEOUS   GENERATION*.  303 

generations  have  been  sufficiently  numerous  to 
spread  the  species  throughout  a  great  part  of 
Europe.  M.  Hoogewerf  showed  a  great  flask  full 
to  the  Dutch  biologists  who  met  at  Utrecht  in 
1891.  M.  L.  Errera  presented  others  in  June  1899, 
to  the  Society  of  Medical  and  Natural  Sciences  at 
Brussels.  To-day  the  great  manufactory  of  Sarg  & 
Co.,  of  Vienna,  is  engaged  in  their  production  on  a 
large  scale  for  industrial  purposes. 

Thus  we  are  able  to  study  this  crystalline  species 
of  glycerine  and  to  determine  with  precision  the 
conditions  of  its  continued  existence.  It  has  been 
shown  that  it  does  not  resist  a  temperature  of  18°,  so 
that  if  precautions  were  not  taken  to  preserve  it, 
a  single  summer  would  suffice  to  annihilate  all  the 
crystalline  individuals  existing  on  the  surface  of  the 
globe,  and  thus  the  species  would  be  extinguished. 

Possible  Extinction  of  a  Crystalline  Species.  —  As 
these  crystals  melt  at  iS3,  this  temperature  represents 
the  point  of  fusion  of  solid  glycerine  or  the  point  of 
solidification  of  liquid  glycerine.  But  the  liquor 
does  not  solidify  at  all  if  its  temperature  falls  below 
18°  C.,  as  we  well  know,  for  it  is  at  that  temperature 
we  use  it  Nor  does  it  solidify  at  zero,  nor  even  at 
18°  below  zero  ;  at  20°,  for  instance,  it  merely  thickens 
and  becomes  pasty.  We  only  know  glycerine,  then,  in 
a  state  of  superfusion,  a  fact  which  chemists  have  not 
learned  without  amazement.  Under  these  conditions, 
so  analogous  to  the  appearance  of  a  living  species,  to 
its  unlimited  propagation  and  to  its  extinction,  the 
mineral  world  offers  a  quite  faithful  counterpart  to 
the  animal  world.  The  living  body  illustrates  here 
the  history  of  the  brute  body  and  facilitates  its 
exposition.  Inversely,  the  brute  body  in  its  turn 


304  LIFE    AND    DEATH. 

throws  remarkable  light  on  the  subject  of  the  living 
body,  and  on  one  of  the  most  serious  problems 
relative  to  its  origin,  that  of  spontaneous  generation. 

Conclusion. — These  facts  lead  to  one  conclusion. 
Until  the  concourse  of  propitious  circumstances 
favourable  to  their  spontaneous  generation  was 
brought  about,  crystals  were  obtained  only  by 
filiation.  Until  the  discovery  of  electro-magnetism, 
magnets  were  made  only  by  filiation,  by  means  of 
the  simple  or  double  application  of  a  pre-existing 
magnet.  Before  the  discovery  which  fable  attributes 
to  Prometheus,  every  new  fire  was  produced  only  by 
means  of  a  spark  from  a  pre-existing  fire.  We  are 
at  the  same  historical  stage  as  regards  the  living 
world,  and  that  is  why,  up  to  the  present,  there  has 
never  been  formed  a  single  particle  of  living  matter 
except  by  filiation,  except  by  the  intervention  of  a 
pre-existing  living  organism. 


BOOK  V. 

SENESCENCE  AXD   DEATH. 

Chap.  I.  The  different  points  of  view  from  which  death  may  be 
regarded.  —  Chap.  II.  Constitution  of  the  organisms  — 
Partial  death  —  Collective  death.  — Chap.  III.  Physical 
and  chemical  characteristics  of  cellular  death— Necrobiosis. 
Chap.  IV.  Apparent  perennity  of  complex  individuals. — 
Chap.  V.  Immortality  of  the  protozoa  and  of  slightly 
differentiated  cdls. 

WE  grow  old  and  we  die.  We  see  the  beings 
which  surround  us  grow  old  and  disappear.  At  first 
we  see  no  exceptions  to  this  inexorable  law,  and  we 
consider  it  as  a  universal  and  inevitable  law  of 
nature.  But  is  this  generalization  well  founded? 
Is  it  true  that  no  being  can  escape  the  cruel  fate  of 
old  age  and  death,  to  which  we  and  all  the  repre- 
sentatives of  the  higher  animality  are  exposed  ?  Or, 
on  the  other  hand,  are  any  beings  immortal  ?  Biology 
answers  that,  in  fact,  some  beings  are  immortal. 
There  are  beings  to  whose  life  no  law  assigns  a 
limit,  and  they  are  the  simplest,  the  least  differentiated 
and  the  least  perfect.  Death  thus  appears  to  be  a 
singular  privilege  attached  to  organic  superiority,  the 
ransom  paid  for  a  masterly  complexity.  Above  these 
elementary,  monocellular,  undifferentiated  beings, 
which  are  protected  from  mortality,  we  find  others, 
higher  in  their  organization,  which  are  exposed  to 
305 


306  LfFE   AND   DEATH. 

it,  but  with  whom  death"  seems  but  an  accident, 
avoidable  in  principle  if  not  in  fact.  The  anatomical 
elements  of  this  higher  animal  are  a  case  in  point. 
Flourens  once  tried  to  persuade  us  that  the  threshold 
of  old  age  might  be  made  to  recede  considerably,  and 
there  are  biologists  in  the  present  day  who  give  us 
some  glimpse  of  a  kind  of  vague  immortality.  We 
may,  therefore,  ask  our  readers  to  follow  us  in  our 
examination  of  these  re-opened  if  not  novel  questions, 
and  we  shall  explain  the  views  of  contemporary 
physiology  as  to  the  nature  of  death,  its  causes,  its 
mechanisms,  and  its  signs. 


CHAPTER  I. 

VARIOUS   WAYS   OF   REGARDING   DEATH. 

Different  meanings  of  the  word  death — Physiological  distinction 
between  elementary  and  general  death  —  Non-scientific 
opinions — The  ordinary  point  of  view — Medical  point  of 
view. — The  signs  of  death  are  prognostic  signs. 

Different  Meanings  oftlu  WordDeatJi. — An  English 
philosopher  has  asserted  that  the  word  we  translate 
by  "  cause  "  has  no  less  than  sixty-four  different  mean- 
ings in  Plato  and  forty-eight  in  Aristotle.  The  word 
"death"  has  not  so  many  meanings  in  modern 
languages,  but  still  it  has  many.  Sometimes  it 
indicates  an  action  which  is  taking  place,  the  action 
of  dying,  and  sometimes  a  state,  the  state  which 
succeeds  the  action  of  dying.  The  phenomena  it 
connotes  are  in  the  eyes  of  many  biologists  quite 
different,  according  as  we  watch  them  in  an  animal 
of  complex  organization,  or  on  the  other  hand,  in 
monocellular  beings,  protozoa  and  protophytes. 

Physiological  Distinction  between  Elementary  Death 
and  General  Death. — We  distinguish  the  death  of  the 
anatomical  elements,  elementary  death,  from  the 
death  of  the  individual  regarded  as  a  whole,  general 
deatlt.  Hence  we  recognize  an  apparent  death,  which 
is  an  incomplete  and  temporary  suspension  of  the 
phenomena  of  vitality,  and  a  real  death,  which  is  a 
final  and  total  arrest  of  these  phenomena.  When 
307 


3O8  LIFE   AND    DEATH. 

we  consider  it  in  its  essential  nature  (assumed,  but 
not  known)  we  look  on  it  as  the  contrary  of  life,  as 
did  the  Encyclopaedia,  Cuvier,  and  Bichat ;  or  \ve 
regard  it  with  others  either  as  the  consequence  of 
life,  or  simply  as  the  end  of  life. 

Non-scientific  Opinions.  —  What  is  death  to  those 
outside  the  realm  of  science  ?  First  of  all  we  find  the 
consoling  solution  given  by  those  who  believe  death 
to  be  the  commencement  of  another  life.  We  next 
find  ourselves  involved  in  a  confused  medley,  an 
infinite  diversity  of  philosophical  doubt  and  super- 
stition. "  A  leap  into  the  unknown,"  says  one. 
"  Dreamless  and  unconscious  night,"  says  another. 
And  again,  "  A  sleep  which  knows  no  waking." 
Or,  with  Horace,  "  the  eternal  exile,"  or  with 
Seneca,  annihilation.  Post  mortem  nitiil ;  ipsaqne 
mors  nihil. 

The  idea  which  is  constantly  supervening  in  the 
midst  of  this  conflict  of  opinion  is  that  of  the 
breaking  up  of  the  elements,  the  union  of  which 
forms  the  living  being.  It  has,  as  we  shall  see,  a 
real  foundation  which  may  perhaps  receive  the 
support  of  science.  We  shall  not  find  that  the  best 
way  of  defining  death  is  to  say  that  it  consists  of  the 
"  dissolution  of  the  society  formed  by  the  anatomical 
elements,  or  again,  in  the  dissolution  of  the  conscious- 
ness that  the  individual  possesses  of  himself — i.c ,  of 
the  existence  of  this  society."  It  is  the  rupture  of 
the  social  bond.  The  old  idea  of  dispersion  is  a 
variant  of  the  same  notion.  But  the  ancients 
evidently  could  not  understand,  as  we  do,  the  nature 
of  these  elements  which  are  associated  to  form  the 
living  being,  and  which  are  liberated  or  dispersed 
by  death.  We,  as  biologists,  can  see  microscopical 


VARIOUS   WAYS   OF   REGARDING    DEATH.          309 

organic  unity  with  a  real  objective  existence.  The 
ancients  were  thinking  of  spiritual  elements,  of 
principles,  of  entities.  To  the  Romans,  who  may  be 
said  to  have  held  that  there  are  three  souls,  death 
was  produced  by  their  separation  from  the  body. 
The  first,  the  breath,  the  spiritus,  mounting  towards 
celestial  regions  (aslra  petif) ;  the  second,  the  shade, 
remaining  on  the  surface  of  the  earth  and  wandering 
around  the  tombs  ;  the  third,  the  manes,  descending 
to  the  lower  regions.  The  belief  of  the  Hindoos  was 
slightly  different  The  body  returned  to  the  earth, 
the  breath  to  the  winds,  the  fire  of  the  glance  to  the 
sun,  and  the  ethereal  soul  to  the  world  of  the  pure. 
Such  were  the  ideas  of  mortal  dispersion  formed  by 
ancient  humanity. 

Modern  science  takes  a  more  objective  point  of 
view.  It  asks  by  what  facts,  by  what  observable 
events  death  is  indicated.  Generally  speaking,  we 
may  say  that  these  facts  interrupt  an  interior  state 
of  things  which  was  life  and  to  which  they  put  an 
end  Thus  death  is  defined  by  life.  It  is  the 
cessation  of  the  events  and  of  the  phenomena  which 
characterize  life.  We  must,  therefore,  know  what 
life  is  to  understand  the  meaning  of  death.  How 
wise  was  Confucius  when  he  said  to  his  disciple, 
Li-Kou : — "  If  we  do  not  know  life,  how  can  we 
know  death  ?  "  According  to  biology  there  are  two 
kinds  of  death  because  there  are  two  kinds  of  life ; 
elementary  life  and  death  correspond  just  as  general 
life  and  death  do,  and  this  is  where  scientific  opinion 
diverges  from  commonly  received  opinion. 

What  cares  the  man  who  reasons  as  most  human 
beings  do,  about  this  life  of  the  anatomical  elements 
of  his  body,  the  existence  and  the  silent  activity  of 


3IO  LIFE   AND    DEATH. 

which  are  in  no  way  revealed  to  him.  What  does 
their  death  matter  to  him  ?  To  him  there  is  but  one 
poignant  question,  that  of  being  separated  or  not 
being  separated  from  the  society  of  his  fellows. 
Death  is  no  longer  to  feel,  no  longer  to  think  ;  it  is 
the  assurance  that  one  will  never  feel,  one  will  never 
think  again.  Sleep,  dreamless  sleep,  is  already  in  our 
eyes  a  kind  of  transient  death ;  but,  when  we  fall  asleep 
we  are  sure  of  waking  again.  There  is  no  awaking 
from  the  sleep  of  death.  But  that  is  not  all.  Man 
knows  that  death,  this  dreamless  sleep  that  knows  no 
waking,  will  be  followed  by  the  dissolution  of  his 
body.  And  what  a  dissolution  will  there  be  for  the 
body,  the  object  of  his  continual  care !  Remember 
the  description  of  Cuvier — the  flesh  that  passes  from 
green  to  blue  and  from  blue  to  black,  the  part  which 
flows  away  in  putrid  venom,  the  other  part  which 
evaporates  in  foul  emanations,  and  finally,  the  few 
ashes  that  remain,  the  tiny  pinch  of  mineral?,  saline 
or  earthy,  which  are  all  that  is  left  of  that  once 
animated  masterpiece. 

7 he  Popular  View. — To  the  man  afraid  of  death 
it  seems,  in  the  presence  of  so  great  a  catastrophe, 
that  the  patient  analysis  of  the  physiologist  scrupu- 
lously noting  the  succession  of  phenomena  and  ex- 
plaining their  sequence  is  uninteresting.  He  will 
only  attach  the  slightest  importance  to  knowing  that 
vestiges  of  vitality  remain  in  this  or  that  part  of  his 
body,  if  they  do  not  re-establish  in  every  part  the 
status  quo  ante.  He  cares  not  to  hear  that  a  certain 
time  after  the  formal  declaration  of  his  death  his 
nails  and  his  hair  will  continue  to  grow,  that  his 
muscles  will  still  have  the  useless  faculty  of  con- 
traction, that  every  organ,  every  tissue,  every  element, 


VARIOUS  WAYS   OF    REGARDING    DEATH.          311 

will  oppose  a  more  or  less  prolonged  resistance  to  the 
invasion  of  death. 

Medical  Vicm. — It  is,  however,  these  very  facts  and 
details,  this  why  and  wherefore,  which  interest  the 
physiologist.  The  state  of  mind  of  the  doctor  in  this 
respect,  again,  is  different  When,  for  instance,  the 
doctor  declares  that  such  and  such  a  person  is  dead, 
he  is  really  making  not  so  much  a  statement  of  fact 
as  a  prediction.  How  many  elements  are  still  living 
and  will  be  capable  of  new  birth  in  this  corpse  that 
he  has  before  his  eyes?  That  is  not  what  he  asks 
himself,  nor  is  it  what  we  should  ask  of  him.  He 
knows,  besides,  that  all  these  partial  survivals  will  be 
extinguished  and  will  never  find  the  conditions 
necessary  to  reviviscence,  and  that  the  organization 
will  never  be  restored  to  its  primal  activity  ;  and  this 
is  what  he  affirms.  The  fear  of  premature  burial 
which  haunts  so  many  imaginations  is  the  fear  of  an 
error  in  the  prediction.  It  is  to  avoid  this  that 
practical  medicine  has  devoted  so  much  of  its 
attention  to  the  discovery  of  a  certain — and  early — 
sign  of  death.  By  this  we  understand  the  discovery 
of  a  certain  prognostic  sign  of  general  death.  We 
want  a  prognostic  sign  enabling  us  to  assert  that  the 
life  of  the  brain  is  now  extinguished  and  will  never 
be  reanimated.  And  yet  there  are  in  that  organism 
many  elements  which  are  still  alive.  Many  others 
even  may  be  born  anew  if  we  could  give  them 
suitable  conditions  which  they  no  longer  meet  with 
in  the  animal  machine  now  thrown  out  of  gear. 
What  finer  example  could  we  give  than  the  experi- 
ment of  Kuliabko,  the  Russian  physiologist,  who 
kept  a  man's  heart  working  and  beating  for  eighteen 
hours  after  the  official  verification  of  his  death. 

21 


CHAPTER    II. 

THE    PROCESS    OF    DEATH. 

Constitution  of  organisms. — Partial  lives.— Collective  life.— The 
role  of  apparatus.— Death  by  lesion  of  the  major  appar- 
atus.—The  vital  tripod.— Solidarity  of  the  anatomical 
elements. — Humoral  solidarity. — Nervous  solidarity. — In- 
dependence and  subordination  of  the  anatomical  elements. 

Partial  Lives.  Collective  Life. — With  the  exception 
of  the  physiologist,  no  one,  neither  he  who  is  ignorant 
nor  he  who  is  intellectual,  nor  even  the  doctor, 
troubles  his  head  about  the  life  or  the  death  of  the 
element,  although  this  is  the  basis,  the  real  founda- 
tion, of  the  activity  manifested  by  the  social  body 
and  by  its  different  organs.  The  life  of  the  indi- 
vidual, of  the  animal,  depends  on  these  elementary 
partial  lives  just  as  the  existence  of  the  State  depends 
upon  that  of  its  citizens.  To  the  physiologist,  the 
organism  is  a  federation  of  cellular  elements  unified 
by  close  association.  Goethe  compared  them  to  a 
"  multitude  "  ;  Kant  to  a  "  nation  "  ;  and  others  have 
likened  them  to  a  populous  city  the  anatomical 
elements  of  which  are  the  citizens,  and  which  pos- 
sesses an  individuality  of  its  own.  So  that  the 
activity  of  the  federated  organism  may  be  discussed 
in  each  of  its  parts,  and  then  it  is  elementary  life,  or 
in  its  totality,  and  then  it  is  general  life.  Paracelsus 
and  Bordeu  had  a  glimpse  of  this  truth  when  they 
considered  a  life  appropriate  to  each  part  (vita  proprid] 
312 


THE  PROCESS  OF  DEATH.          313 

and  a  collective  life,  the  life  of  the  whole  {vita 
communist  In  the  same  way  we  must  distinguish 
the  elementary  death,  which  is  the  cessation  of  the 
vital  phenomena  in  the  isolated  cell,  from  the  general 
death,  which  is  the  disappearance  of  the  phenomena 
which  characterised  the  collectivity,  the  totality,  the 
federation,  the  nation,  the  city,  the  whole  in  so  far  as 
it  is  a  unit 

These  comparisons  enable  us  to  understand  how 
general  life  depends  on  the  partial  lives  of  each 
anatomical  citizen.  If  all  die,  the  nation,  the  federa- 
tion, the  total  being  clearly  ceases  to  exist  This 
city  has  an  enormous  population — there  are  thirty 
trillion  cellules  in  the  body  of  man  ;  it  is  peopled 
with  absolutely  sedentary  citizens,  each  of  which  has 
its  fixed  place,  which  it  never  leaves,  and  in  which  it 
lives  and  dies.  It  must  possess  a  system  of  more  or 
less  perfect  arrangements  to  secure  the  material  life 
of  each  inhabitant  All  have  analogous  require- 
ments :  they  feed  very  much  the  same ;  they  breathe 
in  the  same  way;  each  in  fact  has  its  profession, 
industry,  talents,  and  aptitudes  by  which  it  contri- 
butes to  social  life,  and  on  which,  in  its  turn,  it 
depends.  But  the  process  of  alimentation  is  the 
same  for  all.  They  must  have  water,  nitrogenous 
materials  and  analogous  ternaries ;  the  same  mineral 
substances,  and  the  same  vital  gas,  oxygen.  It  is  no 
less  necessary  that  the  wastes  and  the  egesta,  very 
much  alike  in  every  respect,  should  be  carried  off  and 
borne  away  in  discharges  arranged  so  as  to  free  the 
whole  system  from  the  inconvenience,  the  unhealthi- 
ness,  and  the  danger  of  these  residues. 

Secondary  Organisation  in  Organs. — That  is  why, 
as  we  said  above,  the  secondary  organizations  of  the 


314  LIFE   AND   DEATH. 

economy  exist : — the  digestive  apparatus  which  pre- 
pares the  food  and  enables  it  to  pass  into  the  blood, 
into  the  lymph,  and  finally  into  the  liquid  medium 
which  bathes  each  cell  and  constitutes  its  real 
medium ;  the  respiratory  apparatus  which  imports 
the  oxygen  and  exports  the  gaseous  excrement, 
carbonic  acid ;  the  heart  and  the  circulatory  system 
which  distributes  through  the  system  the  internal 
medium,  suitably  purified  and  recuperated.  The 
organization  is  dominated  by  the  necessities  of 
cellular  life.  This  is  the  law  of  the  city,  to  which 
Claude  Bernard  has  given  the  name  of  the  laiv  of  the 
constitution  of  organisms. 

Death  by  Lesion  of  the  Major  Organs.  Vital 
Tripod. — Thus  we  understand  what  life  is,  and  at  the 
same  time  what  is  the  death  of  a  complex  living 
being.  The  city  perishes  if  its  more  or  less  compli- 
cated mechanisms  which  look  after  its  revictualling 
and  its  discharge  are  seriously  affected  at  any  point 
The  different  groups  may  survive  for  a  more  or  less 
lengthy  period,  but  progressively  deprived  of  the 
means  of  food  or  of  discharge,  they  are  finally 
involved  in  the  general  ruin.  If  the  heart  stops, 
there  is  a  universal  famine  ;  if  the  lungs  are  seriously 
injured,  we  are  asphyxiated  ;  if  the  principal  organ 
of  discharge,  the  kidney,  ceases  to  perform  its  allotted 
task,  there  is  a  general  poisoning  by  the  used-up  and 
toxic  materials  retained  in  the  blood. 

We  understand  how  the  integrity  of  the  major 
organs, — the  heart,  the  lungs,  the  kidney, — is  indis- 
pensable to  the  maintenance  of  existence.  We 
understand  that  their  lesion,  by  a  series  of  successive 
repercussions,  involves  universal  death.  We  always 
die,  said  the  doctors  of  old,  because  of  the  failure  of 


THE    PROCESS   OF   DEATH.  315 

one  of  these  three  organs,  the  heart,  th  2  lungs,  or  the 
brain.  Life,  they  said  in  their  inaccurate  language, 
depends  upon  these  as  upon  three  supports.  Hence 
the  idea  of  the  vital  tripod.  But  it  is  not  only  this 
trio  of  organs  which  maintain  the  organism  ;  the 
kidney  and  the  liver  are  no  less  important  In 
different  degrees  each  part  exercises  its  action  on  the 
rest.  Life  is  based  in  reality  on  the  immense 
multitude  of  living  cells  associated  for  the  formation 
of  the  body ;  on  the  thirty  trillion  anatomical  ele- 
ments, each  part  is  more  or  less  necessary  to  all  the 
rest,  according  as  the  bond  of  solidarity  is  drawn  more 
or  less  closely  in  the  organism  under  consideration. 

Death  and  the  Brain. — There  are  indeed  more  noble 
elements  charged  with  higher  functions  than  the  rest 
These  are  the  nervous  elements.  Those  of  the  brain 
preside  over  the  higher  functions  of  animality,  sensi- 
bility, voluntary  movement,  and  the  exercise  of  the 
intellect.  The  rest  of  the  nervous  system  forms  an 
instrument  of  centralization  which  establishes  the 
relations  of  the  parts  one  with  the  other  and  secures 
their  solidarity.  When  the  brain  is  stricken  and  its 
functions  cease,  man  has  lost  the  consciousness  of  his 
existence.  Life  seems  to  have  disappeared.  We  say 
of  a  man  in  this  plight  that  he  no  longer  lives,  thus 
confusing  general  life  with  the  cerebral  life  which  is 
its  highest  manifestation.  But  the  man  or  the 
animal  without  a  brain  lives  what  may  be  called  a 
vegetative  life.  The  human  anencephalic  foetus  lives 
for  some  time,  just  as  the  foetus  which  is  properly 
formed.  Observation  always  shows  that  this  exist- 
ence of  the  other  parts  of  the  body  cannot  be  sus- 
tained indefinitely  in  the  absence  of  that  of  the  brain. 
By  a  series  of  impulses  due  to  the  solidarity  of  the 


3l6  LIFE   AND   DEATH. 

grouping  of  the  parts,  the  injury  received  by  the 
brain  affects  by  repercussion  the  other  organs,  and 
leads  in  the  long  run  to  the  arrest  of  elementary  life 
in  all  the  anatomical  elements.  The  death  of  the 
whole  is  then  complete. 

Doctors  have  therefore  a  two-fold  reason  for  saying 
that  the  brain  may  cause  death.  The  death  of  the 
brain  suppresses  the-  highest  manifestation  of  life,  and, 
in  the  second  place,  by  a  more  or  less  remote  counter 
stroke,  it  suppresses  life  in  all  the  rest  of  the  system. 

Death  is  a  Process. — Besides,  the  fact  is  general. 
The  death  of  one  part  always  involves  the  death  of 
the  rest — i.e.,  universal  death.  A  living  organism 
cannot  be  at  the  same  time  alive  and  a  cemetery.  The 
corpses  cannot  exist  side  by  side  with  the  living 
elements.  The  dead  contaminates  the  living,  or  in 
some  other  way  involves  it  in  its  ruin.  Death  is 
propagated  ;  it  is  a  progressive  phenomenon  which 
begins  at  one  point  and  gradually  is  extended  to  the 
whole.  It  has  a  beginning  and  a  duration.  In  other 
words,  the  death  of  a  complex  organism  is  a  process. 
And  further,  the  end  of  a  simple  organism,  of  a 
protozoan,  of  a  cell,  is  itself  a  process  infinitely 
more  shortened. 

The  very  perfection  of  the  organism  is  therefore  the 
cause  of  its  fragility.  It  is  the  degree  of  solidarity  of 
the  parts  one  with  another  which  involves  the  one  set 
in  the  catastrophe  of  the  rest,  just  as  in  a  delicate 
piece  of  mechanism  the  derangement  of  a  wheel  brings 
nearer  and  nearer  the  total  breakdown.  The  im- 
portant parts,  the  lungs,  the  heart,  the  brain,  suffer  no 
serious  alteration  without  the  reflex  being  felt  through- 
out. But  there  are  also  wheels  less  evident,  the 
integrity  of  which  is  scarcely  less  necessary. 


THE  PROCESS  OF  DEATH.          317 

Tlu  Solidarity  of  tJu  Anatomical  Elements. — The 
cause  of  the  mortal  process — />.,  of  the  extension  and 
the  propagation  of  an  initial  destruction — is  therefore 
to  be  found  in  the  solidarity  of  the  parts  of  the 
organism.  The  closer  it  is  the  greater  do  the  chances 
of  destruction  become,  for  the  accident  which  has 
happened  to  one  will  by  repercussions  affect  the 
others. 

Now  the  solidarity  of  the  parts  of  the  organism 
may  be  carried  out  in  two  ways ;  there  is  a  Jtumoral 
solidarity  and  a  nervous  solidarity. 

Humoral  Solidarity. — Humoral  solidarity  is  realized 
by  the  mixture  of  humours.  All  the  liquids  of  the 
organism  which  have  lodged  in  the  interstices  of  the 
elements  and  which  soak  the  tissues,  are  in  contact 
and  in  relation  of  exchange  one  with  another,  and 
through  the  permeable  wall  of  the  small  vessels  they 
are  in  relation  with  the  blood  and  the  lymph. 

All  the  liquid  atmospheres  which  surround  the 
cells  and  form  their  ambient  medium  have  inter- 
communication. A  change  having  taken  place  in  one 
cellular  group,  and  therefore  in  the  corresponding 
liquid,  modifies  the  medium  of  the  further  or  nearer 
groups,  and  therefore  these  groups  themselves. 

Nervous  Solidarity. — But  the  real  instrument  of  the 
solidarity  of  the  part  is  the  nervous  system.  Thanks 
to  it  in  the  living  machine  the  component  activities  of 
the  cellular  multitude  restrain  and  control  one  another. 
Nervous  solidarity  makes  of  the  complex  being  not  a 
mob  of  cells,  but  a  connected  system,  an  individual  in 
which  the  parts  are  subordinated  to  the  whole  and  the 
whole  to  the  parts  ;  in  which  the  social  organism  has 
its  rights  just  as  the  individual  has  his  rights.  The 
whole  secret  of  the  vital  functional  activity  of  the 


318  LIFE  AND  DEATH. 

complex  being  is  contained  in  these  two  factors  : — the 
independence  and  the  subordination  of  the  elementary 
lives.  General  life  is  the  harmony  of  the  elementary 
lives,  their  symphony. 

Independence  and  Subordination  of  the  Anatomical 
Elements. — The  independence  of  the  anatomical  ele- 
ments results  from  the  fact  that  they  are  the  real 
depositaries  of  the  vital  properties,  the  really  active 
components.  On  the  other  hand  the  subordination  of 
the  parts  to  the  whole  is  the  very  condition  of  the 
preservation  of  form  in  animals  and  plants.  The 
architecture  which  is  characteristic  of  them,  the 
morphological  plan  which  they  realize  in  their 
evolutive  development  which  they  are  ever  preserving 
and  repairing,  form  a  striking  proof  of  this.  This 
dependence  in  no  way  contradicts  the  autonomy  of 
the  elements.  For  when  with  Claude  Bernard  and 
Virchow  we  study  the  circumstances  we  see  that 
the  element  accommodates  itself  to  the  organic 
plan  without  violence  to  its  nature.  It  behaves 
in  its  natural  place  as  it  would  behave  elsewhere, 
if  elsewhere  it  were  to  meet  around  it  the 
same  liquid  medium  which  at  once  is  a  stimulant 
and  a  food.  This  at  least  is  the  conclusion  we 
may  draw  from  experiments  on  transplanting,  or 
on  animal  and  vegetable  grafting.  Neither  the 
neighbouring  elements,  nor  the  whole  system  act  on  it 
at  a  distance  by  a  kind  of  mysterious  induction, 
according  to  the  ideas  of  the  vitalists,  in  order  to 
regulate  the  activity  of  the  element.  They  contribute 
solely  to  the  composition  of  the  liquid  atmosphere 
which  bathes  it.  They  intervene  in  order  to  provide 
it  with  a  certain  environment  whose  very  characteristic 
physical  and  chemical  constitution  regulates  its 


THE    PROCESS   OF   DEATH.  319 

activity.  This  constitution  may  be  some  day  imitated 
by  the  devices  of  experiment  When  that  result  is 
achieved  the  anatomical  element  will  live  in  isolation 
exactly  as  it  lives  in  the  organic  association,  and  the 
mysterious  bond  which  causes  its  solidarity  with  the 
rest  of  the  economy  will  become  intelligible.  In  fact, 
we  may  defer  more  or  less  the  maturity  of  this 
prophecy,  but  there  is  no  doubt  that  we  are  daily 
nearing  its  fulfilment. 

The  general  life  of  the  complex  being  is  therefore 
the  more  or  less  perfect  synergy,  the  ordered  process  of 
elementary  lives.  General  death  is  the  destruction  of 
these  partial  lives.  The  nervous  system,  the  instru- 
ment of  this  harmony  of  the  parts,  represents  the 
social  bond.  It  keeps  most  of  the  partial  elements 
under  its  sway,  and  is  thus  the  intermediary  of  their 
relations.  The  closer  this  dependence,  the  higher  the 
development  of  the  nervous  apparatus,  and  the  better, 
also,  is  assured  the  universal  solidarity  and  therefore 
the  unity  of  the  organism.  Cellular  federation 
assumes  the  characteristic  of  a  unique  individuality 
in  proportion  to  the  development  of  this  nervous 
centralization.  With  an  ideal  perfect  nervous  system 
the  correlation  of  the  parts  would  also  attain  per- 
fection. As  Cuvier  said  :  "  None  could  experience 
change  without  a  change  in  the  rest" 

But  no  animal  possesses  this  extreme  solidarity  of 
the  parts  of  the  living  economy.  It  is  a  philosopher's 
dream.  It  is  the  dream  of  Kant,  to  whom  the  perfect 
organism  would  be  "a  teleological  system,"  a  system 
of  reciprocal  ends  and  means,  a  sum  total  of  parts 
each  existing  for  and  by  the  rest,  for  and  by  the 
whole.  An  organism  so  completely  connected  would 
be  unlikely  to  live.  In  fact,  living  organisms  show  a 


320  LIFE   AND   DEATH. 

little  more  freedom  in  the  interplay  of  their  parts. 
Their  nervous  apparatus  fortunately  does  not  attain 
this  imaginary  perfection  ;  their  unity  is  not  so 
rigorous.  The  idea  of  individuality,  of  individual 
existence,  is  therefore  not  absolute  but  relative. 
There  are  all  degrees  of  it  according  to  the  develop- 
ment of  the  nervous  system.  What  the  man  in  the 
street  and  the  doctor  himself  understand  by  death  is 
the  situation  created  by  the  stopping  of  the  general 
wheels,  the  brain,  the  heart,  and  the  lungs.  If  the 
breath  leaves  no  trace  on  the  glass  held  to  the  mouth, 
if  the  beating  of  the  heart  is  no  longer  perceptible  by 
the  hand  which  touches  or  the  ear  which  listens,  if  the 
movement  and  the  reaction  of  sensitiveness  have 
ceased  to  be  manifest,  these  signs  make  us  conclude 
that  it  is  death.  But  this  conclusion,  as  we  have  said 
before,  is  a  prognostic  rather  than  a  judgment  of  fact. 
It  expresses  the  belief  that  the  subject  will  certainly 
die,  and  not  that  it  is  from  this  moment  dead.  To 
the  physiologist  the  subject  is  only  on  the  way  to  die. 
The  process  has  started.  The  only  real  death  is 
when  the  universal  death  of  all  the  elements  has  been 
consummated. 


CHAPTER  III. 

PHYSICAL    AND     CHEMICAL    CHARACTERS    OF     CEL- 
LULAR DEATH.      NECROBIOSIS.      GROWING  OLD. 

Characteristic  of  elementary  life — Changes  produced  by  death 
in  the  composition  and  the  death  of  the  cell— Schlemm  ; 
Loew  ;  Bokorny  ;  Pfliiger  ;  A.  Gautier ;  Duclaux— The 
processive  character  of  death— Accidental  death— Xecro- 
biosis— Atrophy— Degeneration— So-called  natural  death- 
Senescence— MetchnikofFs  theory  of  senescence— Objec- 
tions. 

ELEMENTARY  death  is  nothing  but  the  suppression 
in  the  anatomical  elements  of  all  the  phenomena  of 
vitality. 

CJiariicteristics  of  Elementary  Life. — The  char- 
acteristic features  of  elementary  life  have  been 
sufficiently  fixed  by  science.  First  of  all,  there  is 
morphological  unity.  All  the  living  elements  have  an 
identical  morphological  composition.  That  is  to  say 
that  life  is  only  accomplished  and  sustained  in  all  its 
fulness  in  organic  units  possessing  the  anatomical 
constitution  of  the  cell,  with  its  cytoplasm  and  its 
nucleus,  constituted  on  the  classical  type.  In  the 
second  place,  there  is  chemical  unity.  The  constituent 
matter,  the  matter  of  which  the  cell  is  built  up,  diverges 
but  little  from  a  chemical  type — a  proteid  complex, 
with  a  hexonic  nucleus,  and  from  a  physical  model 
which  is  an  emulsion  of  granulous,  immiscible  liquids, 
of  different  viscosities.  The  third  character  consists  in 
321 


322  LIFE   AND   DEATH. 

the  possession  of  a  specific  form  acquired,  preserved, 
and  repaired  by  the  element.  The  fourth  character, 
and  perhaps  the  most  essential  of  all,  is  the  property 
of  growth  or  nutrition  with  its  consequence,  namely,  a 
relation  of  exchanges  with  the  external  medium, 
exchanges  in  which  oxygen  plays  considerable  part. 
Finally,  there  is  a  last  property,  that  of  reproduction, 
which  in  a  certain  measure  is  a  necessary  consequence 
of  the  preceding, — i.e.,  of  growth. 

These  five  vital  characters  of  the  elements  are  most 
in  evidence  in  cells  living  in  isolation,  in  microscopical 
beings  formed  of  a  single  cell,  protophytes  and 
protozoa.  But  we  find  them  also  in  the  associations 
formed  by  the  cells  among  one  another — i.e.,  in 
ordinary  plants  and  animals,  multicellular  complexes, 
called  for  this  reason  metaphytes  and  metazoa.  Free 
or  associated,  the  anatomical  elements  behave  in  the 
same  way — feed,  grow,  breathe,  digest  in  the  same 
manner.  As  a  matter  of  fact,  the  grouping  of  the 
cells,  the  relations,  proximity  and  contiguity,  which 
they  assume,  introduce  some  variants  into  the  ex- 
pression of  the  common  phenomena  ;  but  these  slight 
differences  cannot  disguise  the  essential  community 
of  the  vital  processes. 

The  majority  of  physiologists,  following  Claude 
Bernard,  admit  as  valent  and  convincing  the  proof  that 
the  illustrious  experimenter  furnished  of  this  unity 
of  the  vital  processes.  There  are,  however,  a  few 
voices  crying  in  the  wilderness.  M.  Le  Dantec  is  one. 
In  his  new  theory  of  life  he  amplifies  and  exalts  the 
differences  which  exist  between  the  elementary  life  of 
the  proteids  and  the  associated  life  of  the  metazoa. 
In  them  he  can  see  nothing  but  contrasts  and 
deviations. 


PHYSICAL  AND   CHEMICAL  CHARACTERS.         323 

If  this  is  elementary  life,  let  us  ask  what  is 
elementary  death — />.,  the  death  of  the  cell.  And  in 
this  connection  let  us  ask  the  questions  which  we  have 
to  examine  in  the  case  of  animals  high  in  organiza- 
tion, and  of  man  himself.  What  are  the  characteristics 
of  elementary  death  ?  When  the  cell  dies,  is  its  death 
preceded  by  a  growing  old  or  senescence  ?  What  are 
the  preliminary  signs  and  the  acknowledged  symptons  ? 

Ctianges  Produced  by  Death. — The  state  of  death  is 
only  truly  realized  when  the  fundamental  properties 
of  living  matter  enumerated  above  have  entirely 
disappeared.  We  must  follow  step  by  step  this  dis- 
appearance in  all  the  anatomical  elements  of  the 
metazoan. 

Now  the  properties  of  the  cell  are  connected  with 
the  physical  and  chemical  organization  of  living 
matter.  For  them  to  disappear  entirely,  this  organ- 
ization must  be  destroyed  as  far  as  all  that  is  essential 
in  it  is  concerned.  We  cannot  admit  with  the 
vitalists  that  there  is  any  material  difference  between 
the  dead  and  the  living,  and  that  only  an  immaterial 
principle  which  has  escaped  into  the  air  distinguishes 
the  corpse  from  the  animated  being.  In  fact,  the 
external  configuration  may  be  almost  preserved,  and 
the  corpse  may  bear  the  aspect  and  the  forms  of  the 
preceding  state.  But  this  appearance  is  deceptive. 
Something  in  reality  has  changed.  The  structure, 
the  chemical  composition  of  the  living  substance, 
have  undergone  essential  changes.  What  are  these 
changes  ? 

Physical  Clianges. — Certain  physiologists  have 
endeavoured  to  determine  them.  Klemm,  a  botanist, 
pointed  out  in  1895  the  physical  changes  which 
characterize  the  death  of  vegetable  cells — loss  of 


324  LIFE   AND   DEATH. 

turgescence,  fragmentation  of  the  protoplasm,  the 
formation  of  granules,  and  the  appearance  of  vacuoles. 

Chemical  Changes. — O.  Loew  and  Bokorny  laid 
great  stress  in  1886  and  1896  on  the  chemical  changes. 
The  living  protoplasm  according  to  them  is  an 
unstable  proteid  compound.  A  slight  change  would 
detach  from  the  albuminoid  molecule  a  nucleus  with 
the  function  of  aldehyde,  and  at  the  same  time  would 
transform  an  amido-group  into  an  amido-group.  This 
would  suffice  for  the  transition  of  the  protoplasm  from 
the  living  to  the  dead  state.  This  theory  is  based  on 
the  fact  that  the  compounds  which  exercise  a  toxic 
action  on  the  living  cell,  without  acting  chemically  on 
the  dead  albumin,  are  easily  fixed  by  the  aldehydes  ; 
and  on  the  fact  that  many  of  them,  which  attack 
simultaneously  the  living  albuminoids  and  the  dead 
albumin,  easily  combine  with  the  amido-group. 

E.  Pfliiger,  a  celebrated  German  scientist,  has 
considered  living  matter  as  an  albumin  spontaneously 
decomposable,  the  essential  nucleus  of  which  is  formed 
by  cyanogen.  Its  active  instability  would  be  due  to 
the  penetration  into  the  molecule  of  the  oxygen  which 
fixes  on  the  carbon  and  separates  it  from  the  nitrogen. 
Armand  Gautier  has  not  confirmed  this  view. 
Duclaux  (1898)  has  stated  that  the  difference  between 
the  living  and  the  dead  albumin  would  be  of  a  stereo- 
chemical  order. 

Progressive  Character  of  Death.  Accidental  Death. 
— We  have  seen  that  in  general  the  disappearance  of 
the  characteristics  of  vitality  is  not  instantaneous,  at 
least  in  the  natural  course  of  things,  in  complex  organ- 
isms. It  is  the  end  of  a  more  or  less  rapid  process.  But 
death  is  not  instantaneous  in  the  isolated  anatomical 
element  any  more  than  it  is  in  the  protozoan  or 


PHYSICAL  AXD  CHEMICAL  CHARACTERS.        325 

protophyte.  We  most  have  recourse  to  very  violent 
devices  of  destruction  to  kill  the  cell  at  a  blow,  to 
leave  absolutely  nothing  of  its  organization  existing. 
The  protoplasm  of  yeast  when  violently  crushed  by 
Biichner  still  possessed  the  power  of  secreting  soluble 
ferments.  A  powerful  action,  a  very  high  temper- 
ature, is  necessary  to  obtain  the  result.  A  fortidri, 
the  difficulty  increases  in  the  case  of  complex  organ- 
isms, all  of  whose  living  elements  cannot  be  attacked 
at  the  same  moment  by  the  destructive  cause.  A 
mechanical  action,  capable  of  destroying  at  one  blow 
all  the  living  parts  of  a  complex  being,  of  an  animal, 
of  a  plant,  must  be  of  almost  inconceivable  power. 
The  blow  of  a  Xasmyth  hammer  would  not  be  strong 
enough. 

The  chemical  alteration  produced  by  a  very  toxic 
substance  distributed  throughout  the  blood,  and  thus 
brought  into  contact  with  each  element,  would  produce 
a  disorganization  which,  however  rapid  it  were,  could 
not  be  called  instantaneous.  And  the  same  holds 
good  of  physical  agents. 

But  these  are  not  the  processes  of  nature  under 
normal  circumstances.  They  are  accidents  or  devices. 
We  shall  leave  on  one  side  their  consideration  and 
we  shall  only  deal  here  with  the  natural  processes  of 
the  organism. 

Imagine  it  placed  in  a  medium  appropriate  to  its 
needs  and  following  out  without  intervening  com- 
plications the  evolution  assigned  to  it  by  its 
constitution.  Experiment  tells  us  that  this  natural 
evolution  in  every  case  known  to  us  ends  in  death. 
Death  supervenes  sooner  or  later.  For  beings  higher 
in  organization,  which  we  can  bring  into  closer  and 
closer  resemblance  to  man,  we  find  that  they  die  of 


326  LIFE   AND   DEATH. 

disease,  by  accident,  or  of  old  age.  And  as  disease 
is  an  accident,  we  may  naturally  ask  if  what  we  call 
old  age  is  not  also  a  disease. 

However  that  may  be,  the  mortal  process,  being 
never  instantaneous,  has  a  duration,  a  beginning,  a 
development,  an  end — in  a  word,  a  history.  It 
constitutes  an  intermediary  phase  between  perfect 
life  and  certain  death. 

Necrobiosis.  Atrophy.  Degeneration. — The  process 
according  to  the  circumstances  may  be  shortened  or 
prolonged.  When  death  is  the  result  of  violence 
events  are  precipitated.  The  physical  and  chemical 
transformations  of  the  living  matter  constitute  a  kind 
of  acute  alteration  called  by  Schultze  and  Virchow 
necrobiosis.  According  to  the  pathologists,  there  are 
two  kinds  of  necrobiosis : — that  by  destruction,  by 
simple  atrophy,  which  causes  the  anatomical  elements 
to  disappear  gradually  without  undergoing  appreci- 
able modifications  ;  and  necrobiosis  by  degeneration, 
which  transforms  the  protoplasm  into  fatty  matter 
into  calcareous  matter,  into  granulations  (fatty  de- 
generation, calcification,  granulous  degeneration). 
There  is  no  disagreement  as  to  the  causes  of  this 
necrobiosis.  They  are  always  accidental  ;  they 
originate  in  external  circumstances: — the  insufficiency 
of  the  alimentary  materials,  of  water,  of  oxygen ;  the 
presence  in  the  medium  of  real  poisons  destroying 
the  organized  matter ;  the  violent  intervention  of 
physical  agents,  heat,  electricity ;  the  reflex  on  the 
composition  of  the  cellular  atmosphere  of  a  violent 
attack  on  some  essential  organ,  the  heart,  the  lungs, 
the  kidneys. 

Senescence.  Old  Age. — In  a  second  category  we 
must  place  the  mortal  processes,  slow  in  their  move- 


PHYSICAL   AND   CHEMICAL   CHARACTERS.        327 

ment,  in  which  we  cannot  see  the  intervention  of 
clearly  accidental  and  abnormal  disturbing  agents. 
Death  appears  to  be  the  termination  of  a  breaking-up 
proceeding  by  insensible  degrees  in  consequence  of  the 
progressive  accumulation  of  very  small  inappreciable 
perturbations.  This  slow  breaking  up  is  adequately 
expressed  by  the  term — growing  old,  or  senescence. 
The  alterations  by  which  it  is  betrayed  in  the  cell  are 
especially  atropJiic,  but  they  are  also  accompanied, 
however,  by  different  forms  of  degeneration.  An 
extremely  important  question  arises  on  this  subject, 
and  that  is  whether  the  phenomena  of  senility  have 
their  cause  in  the  cell  itself,  if  they  are  inevitably 
found  in  its  organization,  and  therefore  if  old  age  and 
death  are  natural  and  necessary  phenomena.  Or,  on 
the  other  hand,  should  we  consider  them  as  due  to  a 
progressive  alteration  of  the  medium,  the  character  of 
which  would  be  accidental  although  frequent  or 
habitual  ?  This,  in  a  word,  is  the  problem  which  has 
so  often  engaged  the  attention  of  philosophical 
biologists.  Are  old  age  and  death  natural  and 
inevitable  phenomena  ? 

The  recent  experiments  of  Loeb  and  Calkins,  and 
all  similar  observations,  tend  to  attribute  to  the 
phenomenon  of  growing  old  the  character  of  a 
remediable  accident.  But  the  remedy  has  not  been 
found,  and  the  animal  finally  succumbs  to  these  slow 
transformations  of  its  anatomical  elements.  We  then 
say  that  it  dies  of  old  age. 

Metchnikojfs  Theory  of  Senescence.  Objections. — 
Metchnikoff  has  proposed  a  theory  of  the  mechanism 
of  this  general  senescence.  The  elements  of  the 
conjunctive  tissue,  phagocytes,  macrophages,  which 
exist  every \vhere  around  the  specialized  and  higher 

22 


328  LIFE   AND    DEATH. 

anatomical  elements  would  destroy  and  devour  them 
as  soon  as  their  vitality  diminishes,  and  would  take 
their  place.  In  the  brain,  for  example,  it  would  be 
the  phagocytes  which,  attacking  the  nervous  cellules, 
would  disorganize  the  higher  elements,  incapable  of 
defending  themselves.  This  substitution  of  the  con- 
junctive tissue,  which  only  possesses  vegetative  pro- 
perties of  a  low  order,  for  the  nervous  tissues,  which 
possesses  very  high  vegetative  properties,  results  in 
an  evident  breaking-up.  The  gross  element  of 
violent  and  energetic  vitality  stifles  the  refined  and 
higher  element. 

This  expulsion  is  a  very  real  fact.  It  constitutes 
what  is  called  senile  sclerosis.  But  the  active  role 
attributed  to  it  by  Metchnikoff  in  the  process  of 
degeneration  is  not  so  certain.  An  expert  observer 
in  the  microscopic  study  of  the  nervous  system,  M. 
Marinesco,  does  not  accept  this  interpretation  as  far 
as  the  senescence  of  the  elements  of  the  brain  is  con- 
cerned. Diminution  of  the  cell,  the'  decrease  in  the 
number  of  its  stainable  granulations,  chromatolysis, 
the  formation  of  inert,  pigmented  substances — all 
these  phenomena  which  characterize  the  breaking-up 
of  the  cerebral  cells  would  be  accomplished,  according 
to  this  observer,  without  the  intervention  of  the 
conjunctive  elements,  the  phagocytes. 

The  characteristic  of  extensive  and  progressive 
process  presented  by  death  necessitates  in  a  com- 
plex organism,  which  is  a  prey  to  it,  the  existence 
side  by  side  of  living  and  dead  cells.  Similarly,  in 
the  organism  which  is  growing  old,  there  are  young 
elements  and  elements  of  every  age  side  by  side  with 
senile  elements.  As  long  as  the  disorganization  of 
the  last  has  not  gone  too  far,  they  may  be  rejuvenated. 


PHYSICAL  AND  CHEMICAL   CHARACTERS.        32Q 

All  we  have  to  do  is  to  restore  to  them  an  appropriate 
ambient  medium.  The  whole  question  is  one  of 
knowing  and  being  able  to  realize,  for  this  or  that 
part  which  we  wish  to  reanimate  and  to  rejuvenate, 
the  very  special  or  very  delicate  conditions  that  this 
medium  must  fulfil.  As  we  have  said,  success  is 
attained  in  this  respect  as  far  as  the  heart  is  con- 
cerned, and  this  is  why  we  are  able  to  reanimate  and 
to  revive  the  heart  of  a  dead  man.  It  is  hoped  that 
ideas  along  these  lines  will  extend  with  the  progress 
of  physiology. 

After  this  sketch  of  the  conditions  and  of  the 
varieties  of  cellular  death  we  must  return  to  the 
essential  problem  which  is  engaging  the  curiosity  of 
biologists  and  philosophers.  Is  death  unavoidable, 
inevitable?  Is  it  the  necessary  consequence  of  life 
itself,  the  inevitable  issue,  the  inevitable  end  ? 

There  are  two  ways  of  endeavouring  to  solve  this 
question  of  the  inevitability  of  death.  The  first  is  to 
examine  popular  observation,  practised,  so  to  speak, 
unintelligently  and  without  special  precautions.  The 
second  is  to  analyze  everything  we  know  relative  to 
the  conditions  of  elementary  life. 


CHAPTER    IV. 

THE   APPARENT   PERENNITY   OF   COMPLEX 
INDIVIDUALS. 

Millenary  trees — Plants  with  a  definite  rhizome — Vegetables 
reproduced  by  cuttings— Animal  colonies— Destruction  due 
to  extrinsic  causes— Difficulty  of  interpretation. 

POPULAR  opinion  teaches  us  that  living  beings  have 
only  a  transient  existence,  and  as  a  poet  has  said : 
"  Life  is  but  a  flash  between  two  dark  nights."  But, 
on  the  other  hand,  simple  observation  shows  us,  or 
appears  to  show  us,  beings  whose  duration  of  exist- 
ence is  far  longer,  and  practically  illimitable. 

Millenary  Trees. — We  know  of  trees  of  venerable 
antiquity.  Among  these  patriarchs  of  the  vegetable 
world  there  is  a  chestnut  tree  on  Mount  Etna  which 
is  ten  centuries  old,  and  an  ivy  in  Scotland  which  is 
said  to  be  thirty  centuries  old.  Trees  of  5000  years 
old  are  not  absolutely  unknown.  We  may  mention 
among  those  of  that  age  the  famous  dragon  tree1  at 
Orotava,  in  the  island  of  Teneriffe.  Two  other 
examples  are  known  in  California — the  pseudo-cedar, 
or  Tascodiwn,  at  Sacramento,  and  a  Sequoia  gigantea. 
We  know  that  the  olive  tree  may  live  700  years. 
There  are  cedars  800  years  old  and  oaks  of  the  age  of 
1,500  years. 

Plants    with    a    Rhizome. — Vegetable    species    of 

1  Lately  destroyed  in  a  storm.     [Tr.] 
330 


PERENNITY   OF   COMPLEX   INDIVIDUALS.         33! 

almost  unlimited  duration  of  life  are  known  to 
botanists.  Such,  for  instance,  are  plants  with  a 
definite  rhizome,  such  as  colchicum.  Autumnal 
colchicum  has  a  subterranean  root,  the  bulb  of 
which  pushes  out  every  year  fresh  axes  for  a  new 
bloom ;  and  as  each  of  these  new  axes  stretches  out 
an  almost  constant  length,  a  botanist  once  set  himself 
the  singular  problem  of  discovering  how  long  it  would 
take  such  a  foot,  if  suitably  directed,  to  travel  round 
the  world. 

Vegetables  Reproduced  by  Cuttings. — Vegetables  re- 
produced by  slips  furnish  another  example  of  living 
beings  of  indefinite  duration.  The  weeping  willows 
which  adorn  the  banks  of  sheets  of  water  in  the  parks 
and  gardens  throughout  the  whole  of  Europe  have 
sprung,  directly  or  indirectly,  from  slips  of  the  first 
Salix  Babylonica  introduced  to  the  West  May  it  not 
be  said  that  they  are  the  permanent  fragments  of  that 
one  and  the  same  willow  ? 

Animal  Colonies. — These  examples,  as  well  as  those 
furnished  to  zoologists  by  the  consideration  of  the 
polypi  which  have  produced  by  their  slow  growth  the 
reefs,  or  atolls,  of  the  Polynesian  seas,  do  not,  how- 
ever, prove  the  perennity  of  living  beings.  The 
argument  is  valueless,  for  it  is  founded  upon  a  con- 
fusion. It  turns  on  the  difficulty  that  biologists 
experience  in  defining  the  individual.  The  oak  and 
the  polypus  are  not  simple  individuals,  but  associa- 
tions of  individuals,  or,  to  use  Hegel's  expression, 
the  nations  of  which  we  see  the  successive  genera- 
tions. We  give  to  this  succession  of  generations  a 
unique  existence,  and  our  reasoning  comes  to  this, 
that  we  confer  on  each  present  citizen  of  this  social 
body  the  antiquity  which  belongs  to  the  whole. 


332  LIFE   AND   DEATH. 

Destruction  of  the  Social  Individual  due  to  Extrinsic 
Causes, — As  for  the  destruction,  the  death  of  this 
social  individual,  of  this  hundred-year-old  tree,  it 
seems  indeed  that  there  is  no  ground  for  considering 
it  a  natural  necessity.  We  find  the  sufficient  reason 
of  its  usual  end  in  the  repercussion  on  the  individual 
of  external  and  contingent  circumstances.  The  cause 
of  the  death  of  a  tree,  of  an  oak  many  centuries  old, 
is  to  be  found  in  the  ambient  conditions,  and  not  in 
some  internal  condition.  Cold  and  heat,  damp  and 
dryness,  the  weight  of  the  snow,  the  mechanical 
action  of  the  rain,  of  hail,  of  winds  unchained,  of 
lightning;  the  ravages  of  insects  and  parasites — 
these  are  what  really  work  its  ruin.  And  further, 
the  new  branches,  appearing  every  year  and  increas- 
ing the  load  the  trunk  has  to  bear,  increase  the 
pressure  of  the  parts,  and  make  more  difficult  the 
motion  of  the  sap.  But  for  these  obstacles,  external, 
so  to  speak,  to  the  vegetable  being  itself,  it  would 
continue  indefinitely  to  bloom,  to  fructify,  and  as 
each  spring  returned  to  show  fresh  buds. 

Difficulty  of  Interpretation. —  In  this  as  in  all  other 
examples  we  must  know  the  nature  of  the  beings  that 
we  see  lasting  on  and  braving  the  centuries.  Is  it  the 
individual?  Is  it  the  species?  Is  it  a  living  being, 
properly  so  called,  having  its  unity  and  its  in- 
dividuality, or  is  it  a  series  of  generations  succeeding 
one  another  in  time  and  extending  in  space?  In  a 
word,  the  question  is  one  of  knowing  if  we  have  to  do 
with  a  real  tree  or  with  a  genealogical  tree.  We  are 
just  as  uncertain  when  we  deal  with  animals.  What 
is  the  being  that  lasts  on — a  series  of  generations  or 
an  individual?  This  doubt  forbids  us  to  draw  any 
conclusion  from  the  observation  of  complex  beings. 


PERENNITY   OF   COMPLEX   INDIVIDUALS.         333 

We  must  therefore  return  from  them  to  the  elementary 
being,  and  we  must  examine  it  from  the  point  of  view 
of  perennity  or  of  vital  decay.  Let  us  then  ask  the 
questions  that  we  have  already  examined  with  refer- 
ence to  animals  high  in  organization  and  to  man 
himself.  Is  the  death  of  the  cell  an  inevitable  char- 
acteristic? Are  there  any  cells,  protophytes,  protozoa, 
which  are  immortal  ? 


CHAPTER  V. 

THE   IMMORTALITY   OF   THE   PROTOZOA. 

Impossibility  of  life  without  evolution— Law  of  increase  and 
division — Immortality  of  the  protozoa — Death,  a  pheno- 
menon of  adaptation  which  has  appeared  in  the  course  of 
the  ages— The  infusoria— The  death  of  the  infusoria — Two 
kinds  of  reproduction — The  caryogamic  rejuvenescence  of 
Maupas — Calkins  on  rejuvenescence— Causes  of  senescence 
— Impossibility  of  life  without  evolution. 

WE  take  into  account,  a  priori,  the  conditions  that 
must  be  fulfilled  by  the  monocellular  being  in  order 
to  escape  the  inevitability  of  evolution,  of  the  succes- 
sion of  ages,  of  old  age,  and  of  death.  It  must  be 
able  indefinitely  to  maintain  itself  in  a  normal  regime, 
without  changing,  without  increasing,  maintaining  its 
constant  morphological  and  chemical  composition,  in 
an  environment  vast  enough  for  it  to  be  unaltered  by 
the  borrowings  or  the  spendings  resulting  from  its 
nutrition — i.e.,  it  must  remain  constant  in  the  presence 
of  the  constant  being.  We  might  conceive  of  a 
nutrition  perfect  enough,  of  exchanges  exact  enough, 
and  regular  enough,  for  the  state  of  things  to  be 
indefinitely  maintained.  This  would  be  absolute 
permanence  realized  in  the  vital  mobility. 

The  Law  of  Growth  and  Division. — This  model  of 
a  perfect  and  invariable  machine  does  not  exist  in 
nature.     Life  is  incompatible  with  the  absolute  per- 
334 


THE    IMMORTALITY   OF   THE    PROTOZOA.         335 

manence  of  the  dimensions  and  the  forms  of  the  living 
organism. 

In  a  word,  it  is  a  rigorous  law  of  living  nature  that 
the  cell  can  neither  live  indefinitely  without  growth, 
nor  grow  indefinitely  without  division. 

Why  is  this  so?  Why  is  there  this  impossibility 
of  a  regular  regime  in  which  the  cell  would  be  main- 
tained in  magnitude  without  diminution  or  increase? 
Why  has  nutrition  as  a  necessary  consequence  the 
growth  of  the  element?  This  is  what  we  do  not 
positively  know. 

Things  are  so.  It  is  an  irreducible  fact,  peculiar  to 
the  protoplasm,  a  characteristic  of  the  living  matter 
of  the  cell.  It  is  the  fundamental  basis  of  the  pro- 
perty of  generation.  That  is  all  we  can  say  about  it. 
Real  living  beings  have  therefore  inevitably  an  evolu- 
tion. They  are  not  unchangeable.  In  its  simple  form 
this  evolution  consists  in  the  fact  that  the  cell  grows, 
divides,  and  diminishes  by  this  division,  begins  the 
upward  march  which  ends  in  a  new  division.  And 
so  on. 

Immortality  of  the  Protozoa. — It  may  happen,  and 
it  does  happen  in  fact,  that  this  series  of  acts  is 
repeated  indefinitely  at  any  rate  unless  an  accidental 
cause  should  interrupt  it  The  animal  thus  describes 
an  indefinite  curve,  constituted  by  a  series  of  indenta- 
tions, the  highest  point  of  which  corresponds  to  the 
maximum  of  size,  and  the  lowest  point  to  the 
diminution  which  succeeds  the  division.  This  state  of 
things  has  no  inevitable  end  if  the  medium  does  not 
change.  The  being  is  immortal. 

In  fact,  the  compound  beings  of  a  single  cell,  proto- 
phytes  and  protozoa,  the  algae  and  the  unicellular 
mushrooms,  at  the  minimum  stage  of  differentiation, 


336  LIFE    AND    DEATH. 

escape  the  necessity  of  death.  They  have  not,  as 
Weismann  remarks,  the  real  immortality  of  the  gods 
of  mythology,  who  were  invulnerable.  On  the  con- 
trary, they  are  infinitely  vulnerable,  fragile,  and 
perishable;  myriads  die  every  moment.  But  their 
death  is  not  inevitable.  They  succumb  to  accidents, 
never  to  old  age. 

Imagine  one  of  these  beings  placed  in  a  culture 
medium  favourable  to  the  full  exercise  of  its  activities, 
and,  moreover,  wide  enough  in  its  extent  to  be  un- 
affected by  the  infinitely  small  quantities  of  material 
which  the  animal  may  take  from  it  or  expel  into  it. 
Suppose,  for  example,  it  is  an  infusorian  in  an  ocean. 
In  this  invariable  medium  the  being  lives,  increases, 
and  grows  continually.  When  it  has  reached  the 
limits  of  a  size  fixed  by  its  specific  law,  it  divides  into 
two  parts,  which  are  indistinguishable  the  one  from 
the  other.  It  leaves  one  of  its  halves  to  colonize  in  its 
neighbourhood,  and  it  begins  its  evolution  as  before. 
There  is  no  reason  why  the  fact  should  not  be  re- 
peated indefinitely,  since  nothing  is  changed,  either 
in  the  medium  or  in  the  animal. 

To  sum  up.  The  phenomena  which  take  place  in 
the  cell  of  the  protozoan  do  not  behave  as  a  cause  of 
check.  The  medium  allows  the  organism  to  revictual 
and  to  discharge  itself  in  such  a  way  and  with  such 
perfection  that  the  animal  is  always  living  in  a  regular 
regime,  and,  with  the  exception  of  its  growth  and 
later  on  of  its  division,  there  is  nothing  changed 
in  it. 

Death  a  Phenomenon  of  Adaptation — It  appeared  in 
the  Course  of  the  Ages. — This  immortality  belongs  in 
principle  to  all  the  protista  which  are  reproduced  by 
simple  and  equal  division.  If  it  be  remarked  that 


THE   IMMORTALITY  OF  THE    PROTOZOA.        337 

these  rudimentary  organisms  endowed  with  perennity 
are  the  first  living  forms  which  have  shown  them- 
selves on  the  surface  of  the  globe,  and  that  the}-  have 
no  doubt  preceded  many  others — the  multicellular, 
for  instance,  which  are  liable,  on  the  contrary,  to 
decay — the  conclusion  is  obvious: — Life  has  long 
existed  without  death.  Death  has  been  a  pheno- 
menon of  adaptation  which  has  appeared  in  the 
course  of  the  ages  in  consequence  of  the  evolution  of 
species. 

The  Death  of  Infusoria. — We  may  ask  ourselves  at 
what  moment  in  the  history  of  the  globe,  at  what 
period  of  the  evolution  of  its  fauna,  this  novelty, 
death,  made  its  appearance.  The  celebrated  experi- 
ments of  Maupas  on  the  senescence  of  the  infusoria 
seem  to  authorize  us  to  give  a  precise  answer  to  this 
question.  By  means  of  these  experiments  we  are 
led  to  believe  that  death  must  have  appeared 
at  the  same  time  as  sexual  reproduction.  Death 
became  possible  when  this  process  of  generation 
was  established,  not  in  all  its  plenitude,  but  in  its 
humblest  beginnings,  under  the  rudimentary  forms 
of  unequal  division  and  of  conjugation.  This 
happened  when  the  infusoria  began  to  people  the 
waters. 

The  Two  Modes  of  Multiplication. — Infusoria  are,  in 
fact,  capable  of  multiplication  by  simple  division. 
It  is  true  to  say  that  in  addition  to  this  resource,  the 
only  one  which  interests  us  here,  because  it  is  the 
only  one  which  confers  immortality,  they  possess 
another.  They  present  and  exercise  under  certain 
circumstances  a  second  mode  of  reproduction,  caryo- 
gamic  conjugation.  It  is  a  rather  complicated 
process  in  its  detail,  but  it  is  definitively  summed  up 


33^  LIFE   AND   DEATH. 

as  the  temporary  pairing  of  two  individuals,  which 
are  otherwise  very  much  alike,  and  which  cannot  be 
distinguished  as  male  and  female.  They  become 
closely  united  on  one  of  their  faces;  they  reciprocally 
exchange  a  semi-nucleus  which  passes  into  the  con- 
joint individual;  and  then  they  separate.  But 
infusoria  can  be  prevented  from  this  conjunction  by 
regularly  isolating  them  immediately  after  their  birth. 
Then  they  grow,  and  are  constrained  after  a  lapse  of 
time  to  divide  according  to  the  first  method. 

Maupas  has  shown  that  the  infusoria  could  not 
accommodate  themselves  to  this  regime  indefinitely  ; 
they  couIS  not  go  on  dividing  for  ever.  After  a 
certain  number  of  divisions  they  show  signs  of 
degeneration  and  of  evident  decay.  The  size 
diminishes,  the  nuclear  organs  become  atrophied, 
all  the  activities  fail,  and  the  infusorian  perishes. 
It  succumbs  to  this  kind  of  senile  atrophy  unless  it 
is  given  an  opportunity  of  conjugation  with  another 
infusorian  in  the  same  plight.  In  this  act  it  then 
derives  new  strength,  it  grows  larger,  attains  its 
proper  size,  and  builds  up  its  organs  once  more. 
Conjugation  gives  it  life,  youth,  and  immortality. 

A  limentary  Rejuvenescence.  —  Recent  observations 
due  to  Mr.  G.  N.  Calkins,  an  American  biologist, 
and  confirmed  by  other  investigators,  have  shown 
that  this  method  of  rejuvenescence  is  not  the  only 
one,  and  is  not  even  the  most  efficacious.  Conju- 
gation has  no  mysterious,  specific  virtue.  The 
infusoria  need  not  be  married  in  order  to  be 
rejuvenated.  It  is  sufficient  to  improve  their  food. 
In  the  case  of  the  "  tailed "  paramecium  we  may 
substitute  beef  broth  and  phosphates  for  conjuga- 
tion. Calkins  observed  665  consecutive  generations 


THE    IMMORTALITY   OF   THE    PROTOZOA.         339 

without  blemish,  without  exhaustion,  and  without 
any  sign  of  old  age.  Plenty  of  food  and  simple 
drugs  have  successfully  resisted  senility  and  the 
train  of  atrophic  degenerations  which  it  involves. 

Causes  of  Senescence, — As  for  the  causes  of  senes- 
cence which  have  been  remedied  with  such  success, 
they  are  not  exactly  known.  Calkins  thinks  that 
senescence  results  from  the  progressive  losses  to  the 
organism  of  some  substance  essential  to  life.  Con- 
jugation or  intensive  alimentation  would  act  by  build- 
ing up  again  this  necessary  compound.  G.  Loisel 
believes  on  the  contrary  that  it  is  a  matter  of  the 
progressive  accumulation  of  toxic  products  due  to  a 
kind  of  alimentary  auto-intoxication. 


CHAPTER  VI. 

LETHALITY     OF     THE     METAZOA    AND    OF 
DIFFERENTIATED    CELLS. 

Evolution  and  death  of  metazoa.—  Possible  rejuvenescence  of 
the  differentiated  cells  by  the  conditions  of  the  medium. 
—  Conditions  of  the  medium  for  immortal  cells.  —  The 
immortal  elements  of  metazoa.— The  element  in  accidental 
and  remediable  death.— Somatic  cells  and  sexual  cells. 

Evolution  and  Death  of  Metazoa. — We  have  seen 
that  the  infusoria  are  no  longer  animals  in  which 
material  exchanges  take  place  with  sufficient  perfec- 
tion, and  in  which  cellular  division,  the  consequence 
of  growth,  is  produced  with  sufficient  precision  and 
equality  for  life  to  be  carried  on  indefinitely  in 
a  perfect  equilibrium  in  the  appropriate  medium 
without  alteration  or  check.  A  fortiori  we  no 
longer  find  the  perfect  regularity  of  nutritive 
exchange  in  the  classes  above  them.  In  a  word, 
starting  from  this  inferior  group,  th'ere  are  no 
animated  beings  in  the  state  of  existence  which 
Le  Dantec  calls  "  condition  i° "  of  manifested  life  ?  " 
Living  matter,  instead  of  being  continually  kept 
identical  in  conditions  of  identical  media,  is  modified 
in  the  course  of  existence.  It  becomes  dependent  on 
time.  It  describes  a  declining  trajectory;  it  ex- 
periences evolution,  decay,  and  death*  Thus  the 
340 


LETHALITY  OF  THE  METAZOA.        34! 

fundamental  condition  of  invariable  youth  and 
of  immortality  fails  in  all  metazoa.  The  vital 
wastes  accumulate  in  all  through  the  insufnciency 
or  the  imperfection  of  nutritive  absorption  or  of 
excretion.  Life  decays ;  the  organism  progressively 
alters,  and  thus  is  constituted  that  state  of  de- 
crepitude by  atrophy  or  chemical  modification 
which  we  call  senescence,  and  which  ends  in  death. 
To  sum  up,  old  age  and  death  may  be  attributed  to 
cellular  differentiation. 

Possible  Alimentary  Rejuvenescence  of  the  Differ- 
entiated Cells — Conditions  of  Medium. — We  must  add, 
however — as  the  teaching  of  experiments  in  general 
and  in  particular  as  the  teaching  of  the  experiments 
of  Loeb  and  of  Calkins — that  a  slight  change  of  the 
environment,  made  at  the  right  time,  is  capable  of 
re-establishing  equilibrium  and  of  completely  re- 
juvenating the  infusorian.  Senescence  has  not  in 
this  case  a  definitive  any  more  than  an  intrinsic 
character;  a  modification  in  the  composition  of  the 
alimentary  medium  will  successfully  resist  it.  If  we 
are  allowed  to  generalize  this  result,  it  may  be  said 
that  senescence,  the  declining  trajectory,  the  evolu- 
tion step-  by  step  down  to  death,  are  not  for  the 
cells  considered  in  isolation  an  inevitable  and  essen- 
tially inherent  in  the  organism,  and  a  rigorous  con- 
sequence of  life  itself  They  preserve  an  accidental 
character.  In  senescence  and  death  there  is  no 
really  natural,  internal  cause,  inexorable,  and  irre- 
mediable, as  was  claimed  in  the  past  by  J.  M tiller, 
and  more  recently  by  Cohnheim  in  Germany  and 
Sedgwick  Minot  in  America. 

Conditions  of  the  Medium  for  Immortal  Cells. — As 
for  the  cells  which  are  less  differentiated,  the  proto- 


342  LIFE   AND    DEATH. 

phytes  and  the  protozoa  situated  one  degree  lower  in 
the  scale  than  the  infusoria,  we  must  admit  the 
possibility  of  that  perfect  and  continuous  equilibrium 
which  would  save  them  from  senile  decrepitude. 
And  it  is  quite  understood  that  this  privilege  re- 
mains subordinated  to  the  perfect  constancy  of  the 
appropriate  medium.  If  the  latter  changes,  the 
equilibrium  is  broken,  the  small  insensible  per- 
turbations of  nutrition  accumulate,  vital  activity 
decays,  and  in  sole  consequence  of  the  imperfection 
of  the  extrinsic  conditions  or  of  the  medium,  the 
living  being  finds  itself  once  more  dragged  down  to 
decay  and  to  death. 

Immortal  Elements  of  the  Mctazoa. — All  the  pre- 
ceding facts  and  considerations  refer  to  isolated  cells, 
to  monocellular  beings.  But,  and  this  is  what  makes 
these  truths  so  interesting,  they  may  be  extended  to 
all  cells  grouped  in  collectivity — i.e.,  to  all  the 
animals  and  living  beings  that  we  know.  In  the 
complicated  edifice  of  the  organism,  the  anatomical 
elements,  at  any  rate  the  least  differentiated,  would 
have  a  continual  brevet  of  immortality.  Generally 
speaking,  this  would  be  the  case  for  the  egg,  for  the 
sexual  elements,  and  perhaps,  too,  for  the  white 
globules  of  the  blood,  the  leucocytes.  And,  further, 
around  each  of  these  elements  must  be  realized  the 
invariably  perfect  medium  which  is  the  necessary 
condition.  This  does  not  take  place. 

Elements  in  Accidental  and  Remediable  Death. — As 
for  the  other  elements,  they  are  like  the  infusoria, 
but  without  the  resource  of  conjugation.  The 
ambient  medium  becomes  exhausted  and  intoxicated 
around  each  cell,  in  consequence  of  the  accidents 
which  happen  to  the  other  cells.  Each  therefore 


LETHALITY  OF  THE   METAZOA.  343 

undergoes  progressive  decay,  and  finally  they 
perish — the  decay  and  destruction  being  perhaps 
in  principle  accidental,  but,  in  fact,  they  are  the 
rule. 

The  different  anatomical  elements  of  the  organism 
are  more  or  less  sensitive  to  those  perturbations  which 
cause  senescence,  necrobiosis,  and  death.  There  are 
some  more  fragile  and  more  exposed.  Some  are 
more  resisting,  and  finally,  there  are  some  which 
are  really  immortal.  We  have  just  said  that  the 
sexual  cell,  the  ovum,  is  one.  It  follows  that  the 
metazoan,  man  for  instance,  cannot  entirely  die. 
Let  us  consider  one  of  these  beings.  Its  ancestors, 
so  to  speak,  have  not  entirely  disappeared ;  each  has 
left  the  fertile  egg,  the  surviving  element  from  which 
has  issued  the  being  of  which  we  speak ;  and  when 
it  in  its  turn  has  developed,  part  of  that  ovum  has 
been  placed  in  reserve  for  a  new  generation.  The 
death  of  the  elements  is  not  therefore  universal. 
The  metazoan  is  divided  from  the  beginning  into 
two  parts.  On  the  one  hand  are  the  cells  destined 
to  form  the  body,  somatic  cells.  They  will  die.  On 
the  other  hand  are  the  reproductive,  or  germinal,  or 
sexual  cells,  capable  of  living  indefinitely. 

Somatic  and  Sexual  Cells. — In  this  sense  we  may 
say  with  Weismann  that  there  are  two  things  in 
the  animal  and  in  man — the  one  mortal,  the  soma 
the  body,  the  other  immortal,  the  gennen.  These 
germinal  cells,  as  in  the  case  of  the  protozoa  we 
mentioned  above,  possess  a  conditional  immortality. 
They  are  imperishable,  but  on  the  contrary-,  are 
fragile  and  vulnerable.  Millions  of  ova  are  destroyed 
and  are  disappearing  every  moment.  They  may  die 
by  accident,  but  never  of  old  age. 

23 


344  LIFE   AND   DEATH. 

We  now  understand  that  if  the  protistae  are 
immortal,  it  is  because  these  living  beings,  reduced 
to  a  single  cell,  accumulate  in  it  the  compound 
characters  of  the  somatic  cell  and  germinal  cell, 
and  enjoy  the  privilege  \vhich  is  attached  to  the 
latter. 


CHAPTER  VIL 

MAN.       THE    DfSTDJCT   OF    LIFE    AXD  THE    IX5TIXCT 
OF  DEATH. 


The  miseries  at  bmnanity:  i.  Disease;  :•.  OBd  age.—  Old  age 
considered  as  a  duonic  disease  —  Its  occasional  cause.—  5. 

The  disharmonies  of  human  nateie:  4-  The  instinct  of  life 

MAX'S  unhappy  plight  is  the  constant  theme  of 
philosophies  and  religions.  Without  referring  to  its 
moral  basis,  it  has  a  physical  basis  due  to  four 
causes  —  the  physical  imperfection  or  disharmony  of 
nature,  dkrena*,  old  age.  and  death  —  or  rather  of 
three,  for  what  we  call  old  age  is  perhaps  a  simple 
<KjaBa«aR-  These  are  the  great  sorrows  of  man.  the 
sources  of  all  his  woes.  Disease  attacks  him,  old  age 
awaits  him,  and  death  must  tear  him  from  all  the 
ties  which  he  has  formed.  All  his  pleasures  are 
poisoned  by  the  certain  knowledge  that  they  last 
but  for  a  moment,  that  they  are  as  precarious  as  his 
health,  his  youth,  and  his  hie  itself. 

§»  DISEASE. 

Disease,  frequent,  constant,  and  inevitable  as  it  is, 

is,  however,  nothing  but  a  fact  outside  the  natural 

order.     Its  character  is  clearly  accidental,  and  it 

interrupts  the  normal  cycle  of  evolution-     Medical 

545 


346  LIFE   AND   DEATH. 

observation  teaches  us,  on  the  other  hand,  that  the 
health  of  the  body  reacts  on  that  of  the  mind;  and 
therefore  man  as  a  whole,  moral  and  physical,  is 
affected  by  disease.  Bacon  described  a  diseased 
body  as  a  jailer  to  the  soul,  and  the  healthy  body  as 
a  host.  Pascal  recognized  in  diseases  a  principle  of 
error.  "  They  spoil  our  judgment  and  our  senses." 

I  am  not  expressing  a  chimerical  hope  when  I 
predict  that  science  will  conquer  disease.  Medicine 
has  at  last  issued  from  the  contemplative  attitude 
of  so  many  centuries ;  it  has  engaged  in  the 
struggle,  and  signs  of  victory  are  already  appearing. 
Disease  is  no  longer  the  mysterious  power  which  it 
was  impossible  to  escape.  Pasteur  gave  to  it  a  body. 
The  microbe  can  be  caught.  In  the  words  of 
Schopenhauer,  an  alteration  of  the  atmosphere  so 
slight  that  it  is  impossible  to  detect  it  by  chemical 
analysis  may  bring  on  cholera,  yellow  fever,  the 
black  plague,  diseases  which  carry  off  thousands  of 
men;  and  a  slightly  greater  alteration  might  endanger 
all  life.  The  at  once  mysterious  and  terrifying  spec- 
tacle of  the  cholera  at  Berlin  in  1831  had  such  an 
effect  on  the  philosopher  that  he  fled  in  terror  to 
Frankfort.  It  has  been  said  that  this  was  the  origin 
of  his  pessimism,  and  that  but  for  this  he  would  have 
continued  to  teach  idealistic  philosophy  in  some 
Prussian  university.  L.  Hartmann,  another  cele- 
brated leader  of  contemporary  pessimism,  has  also 
said  that  disease  will  always  be  beyond  the  resources 
of  medicine.  Facts  have  given  the  lie  to  these 
sombre  prognostics.  The  microbic  origin  of  most  in- 
fectious diseases  has  been  recognized.  The  discovery 
of  attenuated  poisons  and  serums  has  diminished 
their  gravity.  An  exact  knowledge  of  methods  of 


MAN.      THE    INSTINCT   OF   LIFE    AND    DEATH.      347 

contagion  has  enabled  us  to  erect  against  them  im- 
pregnable barriers.  Cholera,  yellow  fever,  the  plague 
knock  in  vain  at  our  doors.  Diphtheria,  dreaded  by 
every  mother,  has  partially  lost  its  deadly  character. 
Puerperal  fever  and  blindness  of  the  new-born  child 
are  tending  to  disappear.  Legend  tells  us  that 
Buddha  in  his  youth,  frightened  at  the  sight  of  a 
sick  man,  expressed  in  his  father's  presence  the  wish 
to  be  always  in  perfect  health  and  sheltered  from 
disease.  The  King  answered:  "My  son!  you  are 
asking  the  impossible."  But  it  is  towards  the 
realization  of  this  impossibility  that  we  are  on  our 
way.  Science  is  repelling  the  attacks  of  disease. 

§  2.  OLD  AGE. 

Old  age  is  another  sorrow  of  humanity.  The 
stage  of  existence  in  which  the  strength  grows  less 
and  never  grows  greater,  and  in  which  a  thousand 
infirmities  appear,  is  not,  however,  a  stage  universal 
in  animals.  Most  of  them  die  without  our  perceiving 
in  them  any  apparent  signs  of  senile  weakness.  On 
the  other  hand,  some  vegetables  exhibit  these  signs. 
Some  trees  are  old;  but  it  is  in  birds  and  mammals 
that  this  decay,  with  the  train  of  evils  which  accom- 
panies it,  becomes  a  very  marked  phase  of  existence. 
In  man  to  debility  is  added  a  bodily  shrinkage,  grey 
hairs,  withered  skin,  and  the  wearing  out  and  loss  of 
teeth.  The  exhausted  and  atrophied  organism  offers 
a  favourable  field  to  all  intercurrent  diseases  and  to 
every  cause  of  destruction.  It  is  this  discrepitude 
which  makes  old  age  so  hateful.  All  desire  to  be 
old,  said  Cicero;  and  when  they  are  old,  they  say 
that  old  age  has  come  quicker  than  they  expected. 


34^  LIFE   AND    DEATH. 

La  Bruyere  expresses  it  in  an  apothegm,  "We  want 
to  grow  old,  and  we  fear  old  age."  One  would  like 
longevity  without  old  age. 

But  can  life  be  prolonged  without  senility  diminish- 
ing its  value?  Metchnikoff  thinks  it  can.  He 
more  or  less  clearly  catches  a  glimpse  of  a  normal 
evolution  of  existence  which  would  make  it  longer 
and  nevertheless  exempt  from  senile  decay. 

It  is  remarkable  that  we  have  so  few  scientific  data 
on  the  old  age  of  man,  and  we  have  still  fewer  on 
that  of  animals.  The  biologist  knows  no  more  than 
the  layman.  The  old  age  of  the  dog  is  betrayed  by 
its  gait.  Its  coat  loses  its  lustre,  just  as  in  disease. 
The  hair  whitens  around  the  forehead  and  the 
muzzle.  The  teeth  grow  blunt  and  drop  out.  The 
character  loses  its  gaiety  and  becomes  gloomy;  the 
animal  becomes  indifferent.  He  ceases  to  bark,  and 
often  becomes  blind  and  deaf. 

It  is  admitted  that  senile  degeneration  is  due  to  an 
alteration  affecting  most  of  the  tissues.  The  cells, 
the  special  anatomical  elements  of  the  liver,  the 
kidney,  and  the  brain  are  reduced  by  atrophy  and 
degeneration.  At  the  same  time,  the  conjunctive 
woof  which  serves  them  as  a  support  develops,  on 
the  contrary,  at  the  expense  in  a  measure  of  the 
higher  elements.  For  this  reason  the  tissues  harden. 
We  know  that  the  flesh  of  old  animals  is  tough.  We 
know  in  pathology  that  this  is  happening  to  the 
tissues.  It  is  due  to  growth,  to  injury  to  the 
active  and  important  elements,  to  the  elements  of 
support  of  the  organs.  They  form  a  tissue  some- 
times called  packed  tissue,  to  show  its  secondary  role 
with  reference  to  the  elements  which  are  deposited 
in  it.  This  kind  of  degeneration  of  the  organs  is 


MAN.     THE  INSTINCT  OF  LIFE  AND  DEATH.      34Q 

known  as  sclerosis  It  constitutes  the  charasteristic 
lesion  of  a  certain  number  of  chronic  diseases;  and 
these  diseases  are  serious,  for  the  stifling  of  the 
characteristic  elements  by  the  less  important  ele- 
ments of  the  conjunctive  or  packed  tissue  results  in 
the  more  or  less  complete  reduction  or  suppression 
of  the  function. 

The  blood  vessels  also  undergo  this  transformation, 
and  what  we  may  call  universal  trouble  and  danger 
ensue.  This  sclerosis  of  the  arteries,  this  arterio- 
sclerosis, not  only  deprives  the  walls  of  the  blood 
vessels  of  the  suppleness  and  elasticity  which  are 
necessary  for  the  proper  irrigation  of  the  organs,  but 
it  makes  them  more  fragile.  Thus  it  becomes  a 
cause  of  hemorrhage,  which  is  a  very  serious  matter 
as  far  as  the  brain  and  lungs  are  concerned. 

It  is  remarkable  that  the  alteration  of  the  tissues 
during  old  age  should  be  exactly  similar  to  this. 
This  is  inferred  from  the  few  researches  that  have 
been  made  on  the  subject — from  those  of  Demange 
in  1886,  of  Merkel  in  i8qi,  and  finally  from  the 
researches  of  Metchnikoff  himself.  It  is  a  generalized 
sclerosis.  As  its  consequence  we  have  the  lowering 
of  the  proper  activity  of  the  organs  and  the  danger 
of  cerebral  hemorrhage  created  by  arterio-sclerosis. 
The  transformations  of  the  tissues  in  old  men  are 
therefore  summed  up  in  the  atrophy  of  the  important 
and  specific  elements  of  the  tissues,  and  their  replace- 
ment by  the  hypertrophied  conjunctive  tissue.  This 
sclerosis  is  comparable  to  that  of  chronic  diseases; 
it  is  a  pathological  condition.  Thus  old  age,  as  we 
understand  it,  is  a  chronic  disease  and  not  a  normal 
phase  of  the  vital  cycle. 

On  the  other  hand,  if  we  ask  ourselves  what  is  the 


350  LIFE  AND  DEATH. 

origin  of  the  scleroses  which  engender  chronic 
diseases,  we  find  that  they  are  due  to  the  action  of 
various  poisons,  among  which  syphilitic  poison  and 
the  immoderate  use  of  alcohol  take  the  first  place. 
These  are  also  the  usual  causes  of  senile  degenera- 
tion. But  there  must  be  some  other,  some  very 
general  cause  to  explain  the  universality  of  the 
process  of  senescence.  Metchnikoff  thinks  that  he 
has  found  this  cause  in  the  microbes  which  swarm  in 
man's  digestive  tube,  particularly  in  the  large  in- 
testine. Their  number  is  enormous.  Strassburger 
has  given  an  approximate  calculation,  but  words  fail 
to  express  it.  We  have  to  imagine  a  figure  followed 
by  fifteen  zeros.  This  microbic  flora  is  composed  of 
"  bacilli "  and  of  "  cocci,"  and  comprises  a  third  of 
the  rejected  matter.  It  produces  slow  poisons, 
which,  being  at  once  reabsorbed,  pass  into  the  blood 
and  provoke  the  constant  irritation  from  which 
results  arterio-sclerosis  and  the  universal  sclerosis 
of  old  age.  Instead  of  enjoying  a  healthy  and 
normal  old  age,  in  which  the  faculties  of  ripening 
years  are  preserved,  we  drag  out  a  diminished  life, 
a  kind  of  chronic  disease,  which  is  ordinary  old  age. 
This  is  due,  according  to  Metchnikoff,  to  the  para- 
sitism and  the  symbiosis  of  microbic  flora,  lodged  in 
a  part  of  the  economy  in  which  it  finds  all  the  con- 
ditions favourable  to  its  prolific  expansion.  Such  is 
the  specious  theory,  held  to  the  verge  of  intrepidity, 
by  which  this  investigator  explains  the  misery  of  our 
old  age,  and  which  inspires  him  with  the  idea  of  a 
remedy.  For  his  observations  conclude  with  a 
regime,  a  series  of  prescriptions  by  which  the  author 
fancies  that  life  may  be  lengthened  and  the  evils  of 
old  age  swept  from  our  path.  The  dangerous  flora 


MAN.      THE   INSTINCT  OF   LIFE   AND   DEATH.     35! 

must  be  transformed  into  a  cultivated  and  selected 
flora.  Although  the  organ  in  question  may  be  of 
doubtful  utility,  and  although  its  existence,  the 
legacy  of  atavic  heredity,  must  be  considered  as  a 
disharmony  of  human  nature,  Metchnikoff  does  not 
go  so  far  as  to  propose  that  it  should  be  cut  away, 
and  that  we  should  call  in  surgery  to  assist  in  making 
mankind  perfect!  But  the  rational  means  he  pro- 
poses will  be  endorsed  by  the  most  judicious  students 
of  hygiene;  and  their  effect,  if  it  not  as  wonderful 
as  one  hopes  for,  cannot  fail  to  ameliorate  the 
conditions  of  old  age  and  make  it  more  vigorous. 


§  3.  DISHARMONIES  IN  HUMAN  NATURE. 

Another  misery  in  the  condition  of  man  is  due  to 
the  dissidencies  of  his  nature — that  is  to  say,  to  his 
physical  imperfections  and  the  discordancies  which 
exist  between  the  physiological  functions  and  the 
instincts  which  should  regulate  them. 

This  discordance  reigns  throughout  the  physical 
organism.  The  body  of  man  is  not  the  perfect 
masterpiece  it  was  once  supposed  to  be.  It  is 
encumbered  with  annoying  inutilities,  with  rudi- 
mentary organs  that  have  neither  role  nor  function, 
unfinished  sketches  which  nature  has  left  in  the 
different  parts  of  his  body.  Such  are  the  lachrymal 
caruncle,  a  vestige  of  the  third  eyebrow  in  mammals; 
the  extrinsic  muscles  of  the  ear;  the  pineal  gland  of 
the  brain,  which  is  only  the  rudiment  of  an  ancestral 
organ;  the  third  eye,  or  the  Cyclopean  eye  of  the 
saurians.  The  list  is  interminable.  Wiedersheim  has 
counted  in  man  107  of  these  abortive  hereditary 


352  LIFE   AND   DEATH. 

organs,  the  useless  vestiges  of  organs  useful  to  our 
remote  animal  ancestors,  atrophied  in  the  course  of 
ages  in  consequence  of  modifications  that  have  taken 
place  in  the  external  medium. 

These  rudimentary  organs  are  not  only  useless; 
they  are  often  positively  harmful. 

But  the  most  serious  discordance  is  that  which 
exists  between  the  physiological  functions  and  the 
instincts  which  regulate  them.  In  a  well-regulated 
organism  slowly  developed  by  adaptation  the  instincts 
and  the  organs  alike  should  be  in  relation  with  the 
functions.  All  really  natural  acts  are  solicited  by 
an  instinct,  the  satisfaction  of  which  is  at  once  a 
need  and  a  pleasure.  The  maternal  instinct  is 
awakened  at  the  proper  moment  in  animals,  and  it 
disappears  as  soon  as  the  offspring  requires  no  more 
assistance.  A  craving  for  milk  is  shown  in  all  new- 
born children,  and  often  disappears  at  an  early  age. 

Nature  has  endowed  man  as  well  as  the  other 
animals  with  peculiar  instincts,  destined  to  preside 
over  the  different  functions  and  to  ensure  their 
accomplishment.  And,  at  the  same  time,  it  has 
enabled  him  in  a  measure  to  deceive  those  instincts 
and  to  satisfy  them  by  other  means  than  the  execu- 
tion of  the  physiological  acts  with  a  view  to  which 
they  exist.  Love  and  the  instinct  of  reproduction 
exist  in  man  before  the  age  of  puberty.  Canova  felt 
the  spur  of  love  at  the  age  of  five.  Dante  was  in 
love  with  Beatrice  at  nine;  and  Byron,  then  scarcely 
seven,  was  already  in  love  with  Maria  Duff.  On  the 
other  hand,  puberty  has  no  necessary  relation  to  the 
general  maturity  of  the  organism. 

The  family  instinct  is  subject  to  the  same  aberra- 
tions. Man  limits  the  number  of  his  children.  The 


MAN.      THE    INSTINCT   OF    LIFE   AND   DEATH.      353 

Turks  of  to-day  follow  the  ancient  Greeks  in  the 
practice  of  abortion.  Plato  approved  of  the  custom, 
and  Aristotle  sanctioned  its  general  prevalence.  In 
the  province  of  Canton  the  Chinese  of  the  agricul- 
tural classes  kill  two-thirds  of  their  girl  children, 
and  the  same  is  done  at  Tahiti.  All  these  customs 
co-exist  with  the  perfect  love  and  tender  care  of  the 
living  children. 

Because  of  these  different  discordancies  the"  physical 
life  of  man  is  insufficiently  regulated  by  nature. 
Neither  the  physiological  instinct,  nor  the  family 
instinct,  nor  the  social  instinct  is,  in  general,  suffi- 
ciently imperative  and  precise.  Hence,  since  the 
internal  impulse  has  not  sufficient  power,  the  neces- 
sity arises  for  a  rule  of  conduct  exercising  its  influence 
from  without.  Philosophies,  religions,  and  legislation 
have  provided  for  this.  They  have  regulated  man's 
hygiene  and  the  carrying  out  of  his  different  physio- 
logical functions.  Their  control  has,  moreover,  had 
its  hygienic  side.  The  scientific  hvgiene  of  to-day 
has  inherited  their  role. 

The  idea  of  the  fundamental  perversity  of  human 
nature  is  born  of  our  cognizance  of  its  discordancies, 
unduly  amplified  and  exaggerated.  Soul  and  body 
have  been  considered  as  distinctly  discordant  and 
hostile  elements.  The  body,  the  shroud  of  the  soul, 
the  temporary  host,  the  prison,  the  present  source  of 
miseries,  has  been  subjected  to  every  kind  of  mortifi- 
cation. Asceticism  has  treated  the  body  and  all  the 
innate  instincts  as  our  mortal  foes. 

This  suspicion,  this  depreciation  of  human  nature 
was  the  great  error  of  the  mystics.  This  view  was 
as  fatal  as  the  inverse  view  of  pagan  antiquity. 
The  model  of  the  perfect  life  according  to  Greek 


354  LIFE   AND   DEATH. 

philosophy  is  a  life  in  conformity  with  nature.  To 
aim  at  the  harmonious  development  of  man  was  the 
precept  of  the  ancient  Academy,  formulated  by  Plato. 
The  Stoics  and  the  Epicureans  had  adopted  the  same 
principle.  Physical  nature  is  considered  as  good. 
It  gives  us  the  type,  the  rule,  and  the  measure.  The 
moral  rule  itself  is  exactly  appropriate  to  the  physical 
nature.  We  may  say  that  pagan  morality  was 
hygiene,  the  hygiene  of  the  soul  and  the  body  alike; 
the  mens  sana  in  corpore  sano  gave  individual  and 
social  direction.  The  Rationalists,  the  philosophers 
of  the  eighteenth  century,  such  as  Baron  d'Holbach 
and  later  W.  Von  Humboldt,  Darwin,  and  Herbert 
Spencer,  have  adopted  analogous  views.  If  these 
views  have  been  contested,  it  is  because  of  the  im- 
perfections or  aberrations  of  the  natural  instincts  of 
man.  Also,  if  we  wish  to  base  individual  family  or 
social  morality  on  the  natural  instincts  of  man,  it 
must  be  specified  that  these  instincts  are  to  be 
regularized.  We  must  necessarily  appeal  from  the 
imperfect  instincts  of  the  present  to  the  perfected 
instincts  of  the  future.  Their  perfection,  moreover, 
will  only  be  a  more  exact  approximation  to  the  real 
nature  of  man,  and  he,  having  avoided  by  the  aid  of 
science  the  accidents  which  cause  disease  and  senile 
decrepitude,  will  enjoy  a  healthy  youth  and  an  ideal 
old  age. 

The  reason  of  the  discrepancies  between  instinct 
and  function  in  man  is  given  by  the  natural  history 
of  his  development.  We  know  that  man  has  within 
him  original  sin — his  long  atavism.  He  has  sprung, 
according  to  the  transformists,  from  a  simian  stock. 
lie  is  a  cousin,  the  successful  relation,  of  a  type 
of  antinomorphic  monkeys,  the  chimpanzees.  He 


MAX.       THE    INSTINCT   OF    LIFE    AND    DEATH       355 

has  "arrived,"  they  have  remained  undeveloped. 
Probably  he  had  a  common  ancestor  with  them, 
some  dryopithecan  of  an  extinct  species.  From  that 
type  sprang  a  new  type  already  on  the  way  to 
progress,  the  Pithecanthropus  erectus.  Finally,  the 
anthropoid  ancestor  became  one  fine  day  the  father 
of  a  scion,  clearly  superior  to  himself,  a  miraculously 
gifted  being,  man.  Here,  then,  is  no  sign  of  the  slow 
evolution  and  gradual  progress,  which  is  the  doc- 
trine held  at  present  by  Transformists.  The  Dutch 
botanist  De  Vries  has  shown  us,  in  fact,  that  nature 
does  leap:  naturafacit  saltus.  There  would  thus  be 
crises,  as  it  were,  in  the  life  of  species.  At  certain 
critical  epochs  considerable  differences  of  a  specific 
value  appear  in  their  offspring.  It  is  at  one  of  these 
critical  periods  in  the  simian  life  that  man  has 
appeared  as  the  phenomenal  child  of  an  anthropoid. 
He  was  born  with  a  brain  and  an  intellect  superior 
to  those  of  his  humble  parents;  and  on  the  other 
hand,  he  has  inherited  from  them  an  organization 
which  is  only  inadequately  adapted  to  the  new  con- 
ditions of  existence  created  by  the  development  of 
his  sensitiveness  and  his  brain  power.  This  intellect 
is  not  proportioned  to  his  organization,  which  has 
not  developed  at  the  same  rate:  it  protests  against 
the  discordances  which  adaptation  has  not  yet  had 
time  to  efface.  But  it  will  efface  them  in  the  future. 

^THE  INSTINCT  OF  LIFE  AND  THE  INSTINCT 
OF  DEATH. 

The  greatest  discrepancy  of  this  kind  is  the 
knowledge  of  inevitable  death  without  the  instinct 
which  makes  it  longed  for. 


356  LIFE   AND   DEATH. 

There  are  immortal  animals.  Man  is  not  of  the 
number.  He  belongs,  like  all  highly  organized 
beings,  to  the  class  of  beings  which  have  an  end. 
They  die  from  accident  or  from  disease.  They 
perish  in  the  struggle  with  other  animals,  or  with 
microbes,  or  with  external  conditions.  There  are 
certainly  very  few,  if  there  are  any,  which  die  a 
really  natural  death.  And  so  it  is  with  man.  We 
see  old  men  gradually  declining  who  appear  to 
doze  gently  off  into  the  last  sleep,  and  become 
extinguished  without  disease,  like  a  lamp  whose  oil 
is  exhausted.  But  this  is  in  most  cases  only 
apparently  so.  Besides  the  fact  that  the  old  age  to 
which  they  seemed  to  succumb  is  really  a  disease, 
a  generalized  sclerosis,  autopsy  always  reveals  some 
lesion  more  or  less  directly  responsible  for  the  fatal 
issue. 

Man,  like  all  the  higher  animals,  is  therefore 
subject  to  the  law  of  lethality.  But  while  animals 
have  no  idea  of  death  and  are  not  tormented  by  the 
sentiment  of  their  inevitable  end,  man  knows  and 
understands  this  destiny.  He  has  with  the  animals 
the  instinct  of  self-preservation,  the  instinct  of  life, 
and  at  the  same  time  the  knowledge  and  the  fear  of 
death.  This  contradiction,  this  discordance,  is  one 
of  the  sources  of  his  woes. 

Whether  it  be  an  accident  or  the  regular  term  of 
the  normal  cycle,  death  always  comes  too  soon.  It 
surprises  the  man  at  a  time  when  he  has  not  yet 
completed  his  physiological  evolution ;  hence  the 
aversion  and  the  terror  it  inspires.  "We  cannot 
fix  our  eyes  on  the  sun  or  on  death,"  said  La  Roche- 
foucauld. The  old  man  does  not  regard  death  with 
less  aversion  than  the  young  man.  "  He  who  is 


MAX.      THE    INSTINCT   OF   LIFE    AND    DEATH.      357 

most  like  the  dead  dies  with  most  regret."  Man 
knows  that  he  is  not  getting  his  full  measure. 

Further,  all  the  really  natural  acts  are  solicited 
by  an  instinct,  the  satisfaction  of  which  is  a  need 
and  a  joy.  The  need  of  death  should  therefore 
appear  at  the  end  of  life,  just  as  the  need  of  sleep 
appears  at  the  end  of  the  day.  It  would  appear,  no 
doubt,  if  the  normal  cycle  of  existence  were  fulfilled, 
and  if  the  harmonious  evolution  were  not  always 
interrupted  by  accident.  Death  would  then  be 
welcomed  and  longed  for.  It  would  lose  its  horror. 
The  instinct  of  death  would  replace  at  the  wished 
for  moment  the  instinct  of  life.  Man  would  pass 
from  the  banquet  of  life  with  no  other  desire.  He 
would  die  without  regret,  "being  old  and  full  of 
days,"  according  to  the  expression  used  in  the  Bible 
in  the  case  of  Abraham,  Isaac,  and  Jacob.  No 
doubt  there  are  some  analogies  to  this  in  the  insects 
which  only  assume  the  perfect  form  for  the  purpose 
of  procreation  and  immediately  perish  in  their  full 
perfection.  In  these  animals  the  approach  of  death 
is  blended  with  the  intoxication  of  hymen.  Thus 
we  see  some  of  them,  the  ephemerae,  lose  at  that 
moment  the  instinct  of  life  and  the  instinct  of 
self-preservation.  They  allow  themselves  to  be 
approached,  taken,  and  seized,  and  make  no  effort 
at  flight. 

But  what  is  this  full  measure  of  life  which  is 
imparted  to  us?  Metchnikoff  holds  that  the  ages 
attributed  to  several  persons  in  the  Bible  are  very 
probable  Abraham  lived  175  years,  Ishmael  137, 
Joseph  no,  Moses  120.  Buffon  believed  in  the 
existence  of  a  ratio  between  the  longevity  of  animals 
and  the  duration  of  their  growth.  He  fixed  it  at 


358  '    LIFE   AND   DEATH. 

7  :  i.  The  animal  whose  development  lasts  two  years 
would  thus  have  14  years  of  life.  This  law  would 
give  us  140  years,  but  the  figure  is  too  high,  and 
Flourens  has  reduced  the  ratio  to  that  of  5  :  i,  which 
would  still  give  us  120  years.  Plato  died  in  the  act 
of  conversation  at  81 ;  Isocrates  wrote  his  Pana- 
thena'icus  at  94;  Gorgias  died  in  the  full  possession 
of  his  intellect  at  107. 

To  reach  the  end  of  the  promised  longevity  we 
must  neither  count  on  the  elixir  of  life  nor  on  the 
potable  gold  of  the  alchemists,  nor  on  the  stone  of 
immortality  which  did  not  prevent  its  inventor, 
Paracelsus,  from  dying  at  the  age  of  58,  nor  on 
transfusion,  nor  on  Graham's  celestial  bed,  nor  on 
King  David's  gerocomy,  nor  on  any  nostrum  or 
remedy.  Contra  vim  mortis  non  est  medicamen  in 
hortis,  said  the  Salernian  school.  What  Feuchter- 
sleben  said  is  most  true,  "  The  art  of  prolonging  life 
consists  in  not  cutting  it  short,"  and  it  is  a  hygiene, 
but  a  brilliant  hygiene,  such  as  that  of  which 
Metchnikoff  traces  us  the  future  lines,  which  will 
realize  the  desires  of  nature. 

And  now  shall  we  find  that  physiology  has  solved 
the  enigma  proposed  by  the  Sphinx,  and  that  it  has 
answered  these  poignant  questions: — Whence  do 
we  come  ?  whither  do  we  go  ?  what  is  the  end  of 
life  ?  The  end  of  life  is,  to  the  physiologist  as  well 
as  to  Herbert  Spencer,  the  tendency  towards  an 
existence  as  full  and  as  long  as  possible,  towards  a 
life  in  conformity  with  real  nature  freed  from  the 
discordancies  which  still  remain ;  it  is  the  accom- 
plishment of  the  harmonious  cycle  of  our  normal 
evolution.  This  ideal  human  nature,  without  dis- 
cordancies, no  longer  vitiated  as  it  is  at  present  but 


MAN.      THE    INSTINCT  OF   LIFE   AND   DEATH.     359 

improved,  will  be  the  work  of  time  and  science. 
Realized  at  last  it  will  serve  as  a  solid  basis  for 
individual,  family,  and  social  morality.  Healthy 
youth  fit  for  action;  prolonged,  adult  age,  the 
symbol  of  strength ;  normal  old  age,  wise  in  council, 
these  would  have  their  natural  places  in  harmonious 
society.  "  Great  actions,"  said  one  of  old,  "  are  not 
achieved  by  exertions  of  strength,  or  speed,  or  agility, 
but  rather  by  the  prudence,  the  authority,  and  the 
judgment  which  are  found  in  a  higher  degree  in  old 
age."  The  old  age  of  which  Cicero  here  speaks  is 
the  ideal  old  age,  regular  and  normal,  and  not  the 
premature,  deformed,  incapable  and  egoistic  old  age 
which  results  from  a  pathological  condition.  At  the 
end  of  this  full  life,  the  old  man  being  full  of  days, 
will  crave  for  the  eternal  sleep  and  will  resign 
himself  to  it  with  joy.  .  .  . 

Death,  then,  "  the  last  enemy  that  shall  be 
destroyed,"  to  use  the  expression  of  St.  Paul,  will 
yield  to  the  power  of  science.  Instead  of  being 
"  the  king  of  terrors,"  it  will  become  after  a  long 
and  healthy  life,  after  a  life  exempt  from  morbid 
accidents,  a  natural  and  longed  for  event,  a  satisfied 
need.  Then  will  be  realized  the  wish  of  the 
fabulist  :— 

"I  should  like  to  leave  life  at  this  age,  fust  as  one 
leaves  a  banquet,  thanking  the  host,  and  departing." 

Has  this  physiological  solution  of  the  problem  of 
death  the  virtue  attributed  to  it  by  Metchnikoff? 
Is  it  as  optimistic  as  he  thinks  it  is  ?  The  instinct 
of  death  supervening  at  the  end  of  a  normal  and 
well-fHled  cycle  will  no  doubt  facilitate  to  the  aged 
their  departure  on  the  great  voyage.  The  wrench 

24 


360  LIFE   AND   DEATH. 

will  no  longer  exist  for  the  dead.  Will  it  not  exist 
for  those  who  are  left  behind?  And  since  the 
instinct  of  death  can  only  exist  about  the  time  at 
which  death  is  expected,  will  the  young  man  and 
the  man  of  ripened  years  look  with  less  horror  than 
to-day  at  the  law  which  cannot  be  escaped,  when 
they  are  in  full  possession  of  the  instinct  of  life, 
but  warned  of  the  inevitability  of  death  ? 


INDEX  OF  AUTHORS 


Bonasse,  75,  304-5 
Bml&iJi,  12 

derai,  257,  242 

ffllMllll'lUjMftl,  149 

Bondt,  257 

Bnorzis,  2$2 

'••::     :•:.  :     :•:_    :~  : 
:-:v     :•;,:.> 
Bhidbe,  44 

5 


i,  5,  14 


:-.: 
161-2,  175 

j  Con5nrs,245,  246 
CaSQeaet,  272 

_  _  ^  ^  ^_  ^ ^ ^ Calkins,  327,  338 

•4$,  150-1,  tyi,  190-2, 194,  197,     CaBwert,  271 
204,  213,  214-21$,  239  HI  nag.,     GEmadQe,  20 

.I,-:.  ••    -::.:-:::....       :;: 

114,121 
152,     Cbafy.  237,  271 

?:.:-: -•.!.•:     :    ::    ::    :-- 
;:  -M-.    ::.-:::;::.-:;      :;: 

— »«7 
,  i,  6,  JO),  22.27-30, 35,  55, 

::.;    :-:    :  :.j    :::.- 


362 


INDEX   OF   AUTHORS. 


D'ALEMBERT,  20,  59  note,  90,  92 

Gruber,  165,  206,  257 

Dantec,  Le,  48,  52,  55  note,  no, 

Guignard,  161 

148,   173,   198,  201,  203,  213, 

Guillaume,  237,  262,  264,  271,  277 

216,  220,  223  et  seq.,  231,  246, 

Guillemin,  237 

261,  285,  296,  340 

Guldberg,  83 

D'  Arson  val,  126 

Darwin,  3,  46,  167,  258,  354 

HARBERMANN,  183 

Dastre,  A.,  192,  198  note 

Haeckel,   3,   46,    164,    167,    246, 

Davy,  Sir  Humphry,  6l,  80 

251 

Dela  fosse,  282 

Hales,  43 

Delage,  208 

Haller,  27 

Demange,  349 
Democritus,  34,  146 

Hamilton,  Sir  W.  Rowan,  67 
Hammarsten,  180 

Descartes,  3,  9,  35,  37,  40,  73,  91, 

Hartmann,  276,  346 

98 

.Harvey,  43,  160 

Despretz,  126 

Hauy,  282 

Diderot,  245,  246 

Hegel,  170,  331 

Drechsel,  183 

Heidenhain,  3,  29,  30-1 

Dressel,  20 

Heitzmann,  161 

Dubois-Reymond,  44,  58  note,  253 

Ilelmholtz,  44,  56,  58,  67,  90,  97, 

Duclaux,  119,  137,  184,  324 

99,  252 

Dufour,  297 

Helmont,  van,  3,  21,  26,  33,  146, 

Duguet,  264 

250 

Duhem,  62,  264,  265 

Henninger,  302 

Dulong,  126 

Heraclitus,  34 

Dumas,  115,  149,  151-2 

Hertwig,  167 

Hertz,  88 

EPICURUS,  35,  146 

Hess,  91,  98 

Ehrlich,  176 

Hippocrates,  146 

Errera,  52,  193-4,  237,   153,  295, 

Him,  126 

302  ct  set/. 

His,  46 

Euclid,  v. 

Hlasitwetz,  183 

Holbach,  d',  354 

FAYE,  260 

Hoogewerf,  303 

Feuchterslehen,  358 

Ilopkinson,  271 

Flemming,  161 

Humboldt,  W.  von,  354 

Flourens,  20-1,  152,  208,  306,  358 

Fouillee,  242 

INGENHOUSZ,  115 

Fromann,  161 

Izolet,  247 

Fuerth,  183 

JOULE,  53  note,  90-1,  93,  133  ct 

GALEN,  25,  55,  143 

seq.,  143,  152 

Galeotti,  180 

Galileo,  73,  91,  98,  197,  241,  260 

KANT,  312,  319 

Gardair,  19,  248 

Kaup,  213 

Gautier,  A.,  3,  32,   36,  39,    176, 

Kaufmann,  126 

233.  324 

Kelvin,    Lord,    63,    67,    90,   92, 

Gernez,  237,  288,  295  et  seq. 

251-2,    264;    and    the   idea   of 

Glisson,  27 

energy,  66 

Goethe,  170,  312 

Kepler,  29,  241 

Gouy,  266,  268 

Klemm,  323 

Grimaud,  19 

Koelliker,  160 

INDEX  OF  AUTHORS. 


363 


Kossel,  174,  179,  130-1,  \Tf>ctseq. 

Mayer,  R.,  56,  58,  89,  90,  97 

99, 

Kuhne,  45 

IOI 

Kuhm,  216 

Mering,  von,  133,  136 

Kuliabko,  23,  311 

Metchnikoff,  327  et  seq. 

Kunstler,  157,  161-2,  175 

Miescher,  174,  179 

Kuppfer,  161 

Milne-Edwards,  152,  195 

Minot,  341 

LAMMETTRIE,  147 

Miura,  137 

Lamarck,  46 

Mori,  145 

Lapparent,  284 

Mliller,  20,  27,  341 

Lapicque,  140,  145 

Murato,  45 

Langley,  216 

Laplace,  43,  63,  126,  260 

N  AEG  ELI,  1  68 

Laulanie,  103 

Need  ham,  46 

Laurie,  271 

Newton,  58  note,  70,  90-1,  93 

La  Rochefoucauld,  356 

Noorden,  van,  129,  137,  140, 

2IO 

Lavoisier,   3,  28,  30,  36,  43,  65, 

Nussbaum,  165,  206,  215,  217 

117,   121,   126,   128,   143,   176, 

296 

OBERMEYER,  271 

Lea,  216 

Osmond,  237,  271 

Le  Chatelier,  85,  92 
Lechatelier,  H.  and  A.,  271 

Ostwald,  41,  62,  67,  85,  104, 
258,  289,  295  et  seq. 

237, 

Lecocq  de  Boisbaudran,  295 

Leeuwenhoek,  232 

PARACELSLS,  26,  146,  312 

Lefevre,  126 

Pascal,  74,  161 

Legallois,  21 

Pasteur,  53,  191,2224/0?., 

237, 

Ley-dig,  161-2 

250,  288,  346 

Liebermeister,  136 

Payen,  151 

Liebig,  26,  53  note,  117 

Persoz,  152 

Lilienfeld,  179,  247 

Petit,  I  So 

Locke,  23 

Pettenkofer,  210 

Lodge,  271 

Pfeffer.  175,  193 

Loeb,  43,  167,  327,  341 

Pfluger,  12,  56,  135,  144,  176, 

210, 

Loew,  324 

213 

Loisel,  339,  341 

Philpotts,  46 

Lorry,  21 

Pictet,  233 

Longet,  52 

Pitcairn,  35 

Lowitz,  297 
Loye,  192 

Plato,  35,  307 
Plosz,  I  80 

Ludwig,  44,  215 

Poincare,  62 

Poisson,  63 

MACH,  41,  62 

Preyer,  192,  252  el  siq. 

Magendie,  43,  143 

Priestley,  115 

Magy,  37 

Ptolemy,  v. 

Malgaigne,  153 

Pythagoras,  18 

Mallard,  284 

Marinesco,  231,  328 

RAUBER,  237,  288 

Markel,  349 

Raulin,  191 

Maspero,  3,  234 
Matthiesson,  271 

Regnault,  117 
Reinke,  3,  32 

Maupas,  337 
Maxwell,  88 

Renan,  240 
Ribbert,  208 

INDEX   OF   AUTHORS. 


Ribot,  247 

Swann,  159 

Riche,  271 

Swift,  262 

Richet,  50,  126,  140 

Richter,  252 

TAIT,  53  note,  66 

Rindfleisch,  4 

Tammann,  237,  253,  295  et  seq. 

Roberts-  Austen,  237,  271-2 

Thales,  34 

Robin,  62,  177 

Thomson,  Sir  J.  J.,  279 

Rosenthal,  126 

Tissot,  12 

Rouvier,  160 

Tomlinson,  264 

Roux,  46,  165 

Trembley,  22,  206 

Rubner,    129,    130,    140   et    seq., 

Tsuboi,  145 

210 

Tylor,  8 

Rumford,  80 

VERWORN,  206,  252,  257 

SABATIER,  242 

Violette,  295 

Sachs,  161,  194 

Virchow,  318,  326 

Salles-Guyon,  252 
Sanderson,  Burdon,  176 

Voit,  119,  1  33  et  set/.,  210 
Vries,  de,  46,  258,  355 

Scaliger,  241 

Vulpian,  24 

Schleiden,  159 

§ 

Schopenhauer,  346 

WAAGE,  83 

Schwartz,  162 

Waller,  47,  206 

Schultze,  1  60,  326 

Wallerant,  282-3 

Schultzenberger,  174,  162  et  seq  . 
Secchi,  88 

Warburg,  264 
Watt,  76 

Seguin,  58  note,  90 

Weismann,  46,  167,  336,  343 

Senebier,  115 

Wertheim,  264 

Siven,  145 

Whitman,  46 

Spallanzani,  43,  233 

Widersheim,  351 

Spencer,   Herbert,  46,   247,   454, 

Wiedermann,  264 

358 

Wiesner,  167 

Spring,  272 

Willis,  36,  147 

Stahl,  3,  9,  12,  35,  146 

Winternitz,  126 

Stammreich,  137 

Stead,  237 

YUNG,  233 

Stohmann,  129,  130,  140 

Strassburger,  161,  350 

ZUNTZ,  133,  136,  210 

IXDEX  OF  SUBJECTS. 


•:,, 


.- 


: :,-.      .  • 


3«5 


CAIO«TE,  125  •n&r 


if 


iSzrfJ*. 

:       :;::      '    : : 
,33.39,45 


3%  9K;  Ins  of  lio, 
105  rf   xy,  2x9;   afi- 


365 


366 


INDEX   OF   SUBJECTS. 


Energy,  37,  Book  ii.,  passim; 
origin  of  idea  of,  57  ;  theory  of, 
62 ;  the  only  objective  reality, 
64-5 ;  and  kinetic  conception, 
67 ;  mechanical,  69,  73 ;  of  con- 
traction, 75;  kinetic,  76,  83; 
potential,  76,  83;  virtual,  77; 
of  motion  and  position,  79; 
thermal,  and  its  measurements, 
80-2  ;  chemical,  and  its  measure- 
ments, 81-2;  chemical  and  po- 
tential, 83;  materialization  of, 
84 ;  transformations  of,  85  et  seq. ; 
luminous,  86  et  seq. ;  conserva- 
tion of,  90  et  seq.',  capacity  of 
conversion  of,  93 ;  in  biology, 
97 ;  in  living  beings,  99  et  seq.  ; 
physical,  99  et  seq.;  vital,  99 
et  seq. 

Ether,  89 

Equivalence,  law  of,  91 

Excitability,  26-7 


FATIGUE,  of  metals,  264 
Ferments,    butylic    and    butyric, 

193 

Filiation,  250 
Finulism  43 
Food,  a  source  of  energy,  118 

et  seq. ;  thermogenic  and  bio- 

thermogenic  types  of,  131  et  seq. ; 

dynamogenic     type     of,     143; 

nitrogenous,    143 ;    of   animals 

and  plants,  153  et  seq. 
Force,  directive,  16  et  seq.,  32,  39, 

48 ;  vital,  45  ;  an  anthromorphic 

notion,    71  ;     and     work,    74; 

measurement    of,    71  ;    plastic, 

143;  plastic  and  morpho plastic 

forces,  208 

Form,  specific,  199  et  seq.,  281 
Fruits,  acids  of,  136 

GEMMULES,  167,  258 
Generation,    spontaneous,   249  et 

seq.,  294  et  seq. 
Globulin,  178 
Glyceriue,  crystals  of,  302 
Glycogen,  108,  153  et  seq. 
Gramme,  71 


HEAT,  a  mode  of  motion,  61 ;  role 
of  animal  heat,  122  ;  mechanical 
equivalent  of,  Si  ;  an  excretum, 
1 14  ;  a  degraded  form  of  energy. 
88;  converted  into  work,  92 

Heterogeneity,  38,  61 

Histones,  179,  182  et  seq. 

Horse-power,  75 

Hyaloplasm,  161 


IATRO-CHEMISTRY  and  mechanics, 

34-5 

Idioblasts,  167 
Infusoria,  death  of,  337 
Instability,  188  et  seq. 
Instinct,   of  life  and   death,   345 

et  seq. 

Intussusception,  291 
Invariant,  mass  the  first,  63 
Irreversibility,   of   vital   energies, 

104 

Irritability,  27,  196  et  seq. 
Isodynamism,  142 
Isomorphism,  286 


KA,  the,  8 

Kilogrammetre,    72,    75;    per 

second,  75 
Kilowatt.  76 
Kinetic  theory,  39,  62 
Knot,  the  vital,  21 


LEUCIXES,  183 

Leucites,  163 

Life,    defined,    28 ;    latent,    233 ; 

physico-chemical  theory  of,  36 ; 

elementary,  321 
163 


MASS,  and  matter,  63 

Materialism,  34 

Matter,  37,  60,  62  ;  and  mass,  63  ; 
two  kinds  of,  63;  life  of,  236 
et  seq.  ;  brute  and  living,  249 
et  seq.  ;  organization  and  con- 
stitution of,  255  et  seq. ;  defined 
as  extension,  64  ;  conservation 
of,  65 


INDEX  OF   5UBJECT5- 


"  Memory,"  of  •Kfiab,  etc.,  265      | 

Merotomy,  47 
Mecaboiism.  117 

Metizoa,  evolution  and  death  oC. 
340^^. 

-  .          :  - : 
MicelLir  theory,  166  X  sef. 

-  :  ; 

-  .  :.'_.-:          :    - 
'  . 

-Vl'Xitiity  of  stars.  260 
Modality,  twofold,  of  soul,  12 
Mokoles,  o^nic,  254 
Monism,  34,  Chap.  iv.  passim,  63 
':    -      -.      :        -T  -:-  .   :: 

.MflOon,  CJ«HC  ot,  71 ;  ^""^Ft^r  coo- 


- 


:  :  :         :  n;         -      :-: 

231  «f  jay.  ;  fcie  ia  crushed,  257 


:    - 


70,75 

Tital,  15  «f  jvy. 

;:.:.: 


: 


-srs^i?4^  s^==^'; 

M«ahflky,    So,    iSS  rf    ^:-!  ;    of 
Uiing   •alter.  259  «r  ay.  -   of 


CE,  305  rf  *<y. 
,  in  brace  bodies, 


Seaabuitr, 

Solidarity,  of  aKtrowtical  dements. 

•••ocai  znd  nerrcos,  317 
SoaJ,  the,  7  «r  ay. 
Space,  69 

SpeciiicitT,  »itaIT  ^S 
* 


XECKOMOSIS,  326 
Neo-Tiiaiism.  15,  29,  32 
Ne»ility,27 
Nickel,  steels,  277 

- 

Novs,  the,  iS,  239 
Xodems,  179,  iSo  it  setf. 
Nacko-albvMuaokis,     17$;     -p»o-     Scares,  initial  and  deal,  12 

tesds,  177  ft  sty.  Swdling,  167 

N  -:  T--.   :  :  :  -  .    -  -         -  _    -       -  _     . 

Nutrition,    directed,  305,   209  et 

'--'  -  -  '•        '  \  TAGMATA,  169,  175 

'  Teleology,  43 
Tetanus,  tiacter£a  ofr  £03 

0^<W^*<  iieTof1*^  ^ 

ot,  315  ;  perfect,  319 

Trees,  and  immortafity,  330  et  sea. 
PAXGKXFS,  167 
252 


r:ir--.  ".I.-.       -:::---;; 


368 


INDEX    OF    SUBJECTS. 


VACUOI.ES,  113 

Vibrion,  septic,  193 

Vis  viva,  73 

Vital     properties,    theory    of,    29 

et  seq. 
Vitalism,  6,  7,  Chap.  iii.  passim  : 

physico-chemical,  29 
Vitality,  phenomena  of,  216 
Vortex,  vital,  105,  I2O,  229  et  seq. 
Vulcans,  26-7 


WEIGHT,  energy  of  position,  64  ; 
conservation  of,  65  ;  movement 
under  action  of,  271  et  seq. 

Work,  70,  72  ;  and  force,  74,  77  ; 
convened  into  heat,  92  ;  physio- 
logical, 103 

XANTHIC  bases,  180 
i  ZONES,  mctastable  and  labile,  301 


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or  even  French,  handbook  gives,  the  sammary  of  what,  ap  to  the 
moment  in  which  we  write,  is  known  or  conjectued  abort  the  fife  of 
the  great  poe*-~—SatMn£ar  Rmev. 

Life  of  Hunt.    By 


Mr.  Monkhonsehas  brought  together  and  skflfidly  set  in  order 


Life  or  5amuel  Johnson.     By  Colonel  F.  Grant. 

"  Colonel  Grant  has  performed  hb  task  with  dfligence,  son 
good  taste,  and  accuracy.3—  Koutroled  Lemoam  News. 

Life  of  Keats.    By  W.  M.  Rossetti. 

"  Vamable  for  the  amle  information  which  it  contains. 


Life  of  Lessiog.    By  T.  W.  Rolleston. 

"A  picture  of  I^asmg  which  is  virid  an 
detail  for  all  ordinary  purposes."—  Nmtum  (New  York). 

New  York  :  CHAKUS  Scxnam's  Soss. 


A  picture  of  I^asmg  which  is  virid  and  tnitluiil,  and  has  enoogfa  of 
for  all  or 


Life  of  Longfellow.    By  Prof.  Eric  S.  Robertson. 

"A  most  readable  little  book." — Liverpool  Mercury. 

Life  of  Marryat.    By  David  Hannay. 

"  What  Mr.  Hannay  had  to  do — give  a  craftsman-like  account  of  a 
great  craftsman  who  has  been  almost  incomprehensibly  undervalued — 
could  hardly  have  been  done  better  than  in  this  "little  volume." — Man- 
chester Guardian. 

Life  of  Mili.    By  W.  L.  Courtney. 

"  A  most  sympathetic  and  discriminating  memoir." — Glasgow  Herald. 

Life  of  Milton.    By  Richard  Qarnett,  LL.D. 

"  Within  equal  compass  the  life-story  of  the  great  poet  of  Puritanism 
has  never  been  more  charmingly  or  adequately  told." — Scottish  Leader. 

Life  of  Renan.    By  Francis  Espinasse. 

"  Sufficiently  full  in  details  to  give  us  a  living  picture  of  the  great 
scholar,  .  .  .  and  never  tiresome  or  dull." — Westminster  Review. 

Life  of  Dante  Gabriel  Rossetti.     By  J.  Knight. 

"  Mr.  Knight's  picture  of  the  great  poet  and  painter  is  the  fullest  and 
best  yet  presented  to  the  public." — The  Graphic. 

Life  of  Schiller.    By  Henry  W.  Nevinson. 

"  This  is  a  well-written  little  volume,  which  presents  the  leading  facts 
of  the  poet's  life  in  a  neatly  rounded  picture. " — Scotsman. 

"  Mr.  Nevinson  has  added  much  to  the  charm  of  his  book  by  his  spirited 
translations,  which  give  excellently  both  the  ring  and  sense  of  the 
original. " — Manchester  Guardian. 

Life  of  Arthur  Schopenhauer.     By  William  Wallace. 

"  The  series  of  Great  Writers  has  hardly  had  a  contribution  of  more 
marked  and  peculiar  excellence  than  the  book  which  the  Whyte  Professor 
of  Moral  Philosophy  at  Oxford  has  written  for  it  on  the  attractive  and 
still  (in  England)  little-known  subject  of  Schopenhauer." — Manchester 
Guardian. 

Life  of  Scott.     By  Professor  Yonge. 

"  For  readers  and  lovers  of  the  poems  and  novels  of  Sir  Walter  Scott 
this  is  a  most  enjoyable  book." — Aberdeen  Free  Press. 

Life  of  Shelley.    By  William  Sharp 

"  The  criticisms  .  .  .  entitle  this  capital  monograph  to  be  ranked  with 
the  best  biographies  of  Shelley." — Westminster  Review. 

New  York  :  CHARLES  SCRIBNER'S  SONS. 


Life  of  Sheridan.    By  Lloyd  Sanders. 

"To  say  that  Mr.  Lloyd  Sanders,  in  this  volume,  has  produced  the 
best  existing  memoir  of  Sheridan  is  really  to  award  much  fainter  praise 
than  the  book  deserves." — Manchester  Guardian. 

"  Rapid  and  workmanlike  in  style,  the  author  has  evidently  a  good 
practical  knowledge  of  the  stage  of  Sheridan's  day." — Saturday  Review. 

Life  of  Adam  Smith.    By  R.  B.  Haldane,  M.P. 

"  Written  with  a  perspicuity  seldom  exemplified  when  dealing  with 
economic  science. " — Scotsman. 

"Mr.  Haldane's  handling  of  his  subject  impresses  us  as  that  of  a  man 
who  well  understands  his  theme,  and  who  knows  how  to  elucidate  it." — 
Scottish  Leader. 

"  A  beginner  in  political  economy  might  easily  do  worse  than  take  Mr. 
Haldane's  book  as  his  first  text-book." — Graphic. 

Life  of  Smollett.    By  David  Hannay. 

"  A  capital  record  of  a  writer  who  still  remains  one  of  the  great  masters 
of  the  English  noveL" — Saturday  Review. 

"  Mr.  Hannay  is  excellently  equipped  for  writing  the  life  of  Smollett. 
As  a  specialist  on  the  history  of  the  eighteenth  century  navy,  he  is  at  a 
great  advantage  in  handling  works  so  full  of  the  sea  and  sailors  as 
Smollett's  three  principal  novels.  Moreover,  he  has  a  complete  acquaint- 
ance with  the  Spanish  romancers,  from  whom  Smollett  drew  so  much  of 
his  inspiration.  His  criticism  is  generally  acute  and  discriminating;  and 
his  narrative  is  well  arranged,  compact,  and  accurate." — St.  fame*  s 
Gazette. 

Life  of  Thackeray.  By  Herman  Merivaleand  Frank  T.  MarziaLs. 

"  The  book,  with  its  excellent  bibliography,  is  one  which  neither  the 
student  nor  the  general  reader  can  well  afford  to  miss." — Pail  Mall 
Gazette. 

"  The  last  book  published  by  Messrs.  Merivale  and  Marzials  is  full  of 
very  real  and  true  things."— Mrs.  ANNE  THACKERAY  RITCHIE  on 
"  Thackeray  and  his  Biographers,"  in  Illustrated  London  News. 

Life  of  Thoreau.    By  H.  S.  Salt. 

"Mr.  Salt's  volume  ought  to  do  much  towards  widening  the  know- 
ledge and  appreciation  in  England  of  one  of  the  most  original  men  ever 
produced  by  the  United  States."— Illustrated  London  News. 

Life  of  Voltaire.    By  Francis  Espinasse. 

"  Up  to  date,  accurate,  impartial,  and  bright  without  any  trace  of 
affectation. " — Academy. 

Life  of  Whittier.     By  W.  J.  Linton. 

"Mr.  Linton  is  a  sympathetic  and  yet  judicious  critic  of  Whitlier." — 

World. 

Complete   Bibliography  to  each  volume,  by  J.   P.   ANDERSON,   British 
Museum,  London. 

New  York :  CHARLES  SCRIBNER'S  SONS. 


"  An  excellent  series." — TELEGRAPH. 

' ' Excellently  translated,  beautifiilly  bound,  and  elegantly  printed." — 

LIVERPOOL  MERCURY. 
"  Notable  for  the  high  standard  of  taste  and  excellent  jtidgment  that 

characterise  their  editing,  as  well  as  for  the  brilliancy  of  the  literature 

that  they  contain.'" — BOSTON  GAZETTE,  U.S.A. 


Library  of  Humour. 

Cloth  Elegant,  Large  12  mo,  Price  $1.25  per  vol. 
VOLUMES  ALREADY  ISSUED. 

The  Humour  of  France.  Translated,  with  an  Introduction 
and  Notes,  by  ELIZABETH  LEE.  With  numerous  Illustrations  by  PAUL 
FRENZENY. 

The  Humour  of  Germany.  Translated,  with  an  Introduc- 
tion and  Notes,  by  HANS  MULLER-CASENOV.  With  numerous  Illus- 
trations by  C.  E.  BROCK. 

The  Humour  of  Italy.  Translated,  with  an  Introduction  and 
Notes,  by  A.  WERNER.  With  50  Illustrations  and  a  Frontispiece  by 
ARTURO  FIELDI. 

The  Humour  of  America.  Selected,  with  a  copious  Bio- 
graphical Index  of  American  Humorists,  by  JAMES  BARR. 

The  Humour  of  Holland.  Translated,  with  an  Introduction 
and  Notes,  by  A.  WERNER.  With  numerous  Illustrations  by  DUDLEY 
HARDY. 

The  Humour  of  Ireland.  Selected  by  D.  J.  O'DONOGHUE. 
With  numerous  Illustrations  by  OLIVER  PAQUE. 

The  Humour  of  Spain.  Translated,  with  an  Introduction 
and  Notes,  by  SUSETTE  M.  TAYLOR.  With  numerous  Illustrations  by 
H.  R.  MILLAR. 

The  Humour  of  Russia.'  Translated,  with  Notes,  by 
E.  L.  BOOLE,  and,an  Introduction  by  STEPNIAK.  With  50  Illustra- 
tions by  PAUL  FRENZENY. 

New  York  :  CHARLES  SCRIBNER'S  SONS. 


In  One  Volume.     Crown  8w,  Cloth,  Richly  Gilt     Price  $1.25. 

Musicians'  Wit,  Humour,  and 
Anecdote: 

BEIXG 

ON  D1TS  OF   COMPOSERS,   SINGERS,   AND 

INSTRUMENTALISTS  OF  ALL  TIMES. 

By  FREDERICK  J.  CROWEST, 

Author  of  "The  Great  Tone  Poets,77   "The  Story  of  British  Musk:"; 
Editor  of  "The  Master  Musicians"  Series,  etc.,  etc. 

Profusely  Illustrated  with  Quaint  Drawings  by  J.  P.  DOXXE, 

WHAT  ENGLISH  REVIEWERS  SAY:— 
"It  is  one  of  those  delightful  medleys  of  anecdote  of  all  times. 
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"  A  remarkable  collection  of  good  stories  which  must  have  taken  years  of 
perseverance  to  get  together." — Morning  Leader. 

"  A  book  which  should  prove  acceptable  to  two  large  sections  of  the  public 
——those  who  are  interested  in  *irn^Tftggi>  and  those  who  have  an  adeotiate 
sense  of  the  comic."— Globe- 

THE  USEFUL  RED  SERIES. 

Red  Cloth,  Pocket  Size,  Price  50  Cents. 

NEW  IDEAS  ON  BRIDGE.     By  ARCHIBALD  Duxx,  Jux. 
INDIGESTION:    Its    Prevention    and    Cure.      By    F. 

HERBERT  ALDERSON,  M.B. 

ON  CHOOSING  A  PIANO.    By  ALGERXOX  ROSE. 
CONSUMPTION :  Its  Nature,  Causes,  Prevention,  and 

Cure.     By  Dr.  SICARD  DE  PLAUZOLES. 
BUSINESS  SUCCESS.    By  G.  G.  MILLAR. 
PETROLEUM.    By  SYDNEY  H.  NORTH. 
#  INFANT  FEEDING.     By  a  PHYSICIAN. 
THE    LUNGS    IN   HEALTH   AND   DISEASE.    By 

DR.  PAUL  NIEMEYER. 
HOW  TO   PRESERVE  THE  TEETH.    By  a  DENTAL 

SURGEON. 
MOTHER  AND  CHILD.     By  L.  M.  MARRIOTT. 

New  York :  CHARLES  SCRIBXER'S  Soxs. 


Music  Story  Series. 

A  SERIES  OF  LITERARY-MUSICAL  MONOGRAPHS. 
Edited  by  FREDERICK  J.   CROWEST, 

Author  of  "The  Great  Tone  Poets,"  etc.,  etc. 

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THE  STORY  OF  ORATORIO.  By  ANNIE  W.  PATTER- 
SON, B.A.,  Mus.  Doc. 

THE  STORY  OF  NOTATION.  By  C  F.  ABDY  WILLIAMS, 
M.A.,  Mus.  Bac. 

THE  STORY  OF  THE  ORGAN.  By  C.  F.  ABDY 
WILLIAMS,  M.A.,  Author  of  "Bach"  and  "Handel"  ("Master 
Musicians'  Series"). 

THE  STORY  OF  CHAMBER  MUSIC.  By  N.  KILBURN, 
Mus.  BAC.  (Cantab.). 

THE  STORY  OF  THE  VIOLIN.  By  PAUL  STOEVING, 
Professor  of  the  Violin,  Guildhall  School  of  Music,  London. 

THE  STORY  OF  THE  HARP.  By  WILLIAM  H.  GRATTAN 
FLOOD,  Author  of  "  History  of  Irish  Music." 

THE  STORY  OF  ORGAN  MUSIC.  By  C.  F.  ABDY 
WILLIAMS,  M.A.,  Mus.  Bac. 

THE  STORY  OF  ENGLISH  MUSIC  (1604-1904):  being  the 
Worshipful  Company  of  Musicians'  Lectures. 

THE  STORY  OF  MINSTRELSY.  By  EDMONDSTOUNE 
DUNCAN. 

THE  STORY  OF  MUSICAL  FORM.  By  CLARENCE 
LUCAS. 

LATEST    ADDITIONS. 

THE  STORY  OF  OPERA.  By  E.  MARKHAM  LEE,  Mus. 
Doc. 

THE  STORY  OF  THE  CAROL.  By  EDMONDSTOUNE 
DUNCAN. 

New  York:  CHARLES  SCRIBNER'S  SONS. 


The  Makers  of  British  Art. 

A  Series  of  Illustrated  Monographs 

Edited  by 

James     A.    Manson. 

nhntratcd  with  Photogravure  Portraits  ;  Halftone  and  TJn>.  Rf  pml^  iln^ 
of  the  Best  Pictnts. 

Square  Cream  &vo,  Cloth,  $1.25  tut. 

LANDSEER,  SIR  EDWIN.     By  the  EDITOR. 

"  This  little  volume  may  rank  as  the  ™r*A  rtmnftnr  ^""Pff  of  !-••*«••• 
that  the  world  is  likely  to  possess."  —  Times. 

REYNOLDS,  SIR  JOSHUA.  Bv  ELSA  D'ESTERRE- 
KEELING. 

"  An  admirable  little  volume  .  .  .  Miss  Keeling  writes  TOT  justly  and 
sympathetically.  "-Z>«^  Tciegratk. 

"  Useful  as  a  handy  work  of  reference.  "— 


TURNER,  J.  W.  M.      By  ROBERT  CHIGNELL,  Author  of 

"The  Life  and  Paintings  of  Vicat  Cole,  R.A.* 
"This  book  is  thoroughly  competent,  and  at  the  same  tine  it  B  in  the  best 
sense  popular  in  style  and  treatment."  —  Literary  tftnr-d. 

ROMNEY,  GEORGE.  By  SIR  HERBERT  MAXWELL, 
BART.,  F.R.S. 

"  Sir  Herbert  Maxwell's  brightly-  written  and  accurate  monograph  win  not 
disappoint  even  exacting  students,  whilst  its  ebaiming  irpntductinns  are  cer- 
tain to  render  it  an  attractive  gift-book."  —  "tfmmfrni 

"  It  is  a  pleasure  to  read  snch  a  biography  as  this,  so  well  considered,  and 
written  with  such  insight  and  literary  *3aXL"—Daujr  Xfms. 

WILKIE,  SIR  DAVID.     By  PROFESSOR  BAYXE. 
CONSTABLE,  JOHN.     By  the  EARL  OF  PLYMOUTH. 
RAEBURN,  SIR  HENRY.     By  EDWARD  PINNINGTON. 
GAINSBOROUGH,  THOMAS.     By  A.  E.  FLETCHER. 
HOGARTH,  WILLIAM.     By  PROF.  G.  BALDWIN  BROWN. 
MOORE,  HENRY.     By  FRANK  J.  MACLEAN. 
LEIGHTON,  LORD.     By  EDGCUMBE  STALKY. 
NORLAND,  GEORGE.     By  D.  H.  WILSON,  M.A.,  LL.M. 
WILSON,  RICHARD.     By  BEAUMONT  FLETCHER. 
*  MILLAIS,  SIR  JOHN  EVERETT.     By  J.  EADIE  REID. 

New  York:  CHAKUS  SCRIBNER'S  So.vs. 


The  Contemporary  Science  Series. 

Edited  by  Havelock  Ellis. 
* 

.  S  1 2 mo.     Cloth.     Price  $\ .$& per  Volume. 

|>£  I.  THE  EVOLUTION  OF  SEX.     By  Prof.  PATRICK  GEDDES 

"c  H  and  J.  A.  THOMSON.     With  90  Illustrations.     Second  Edition. 

w  ~  "  The  authors  have  brought  to  the  task — as  indeed  their  names  guarantee 

•g  D  — a  wealth  of  knowledge,  a  lucid  and  attractive  method  of  treatment,  and  a 

«  £  rich  vein  of  picturesque  language." — Nature. 

J*  II.  ELECTRICITY  IN  MODERN  LIFE.  By  G.  W.  DE 
'E Q  TUNZELMANN.  With  88  Illustrations. 

^  >•  "  A  clearly  written  and  connected  sketch  of  what  is  known  about  elec- 
c-""  tricity  and  magnetism,  the  more  prominent  modern  applications,  and  the 
.o  f  principles  on  which  they  are  based." — Saturday  Review. 

||  III.  THE    ORIGIN    OF    THE    ARYANS.      By   Dr.    ISAAC 

^  I  TAYLOR.     Illustrated.     Second  Edition. 

r  g  "Canon  Taylor  is  probably  the  most  encyclopaedic  all-round  scholar  now 

,c  £  living.     His  new  volume  on  the  Origin  of  the  Aryans  is  a  first-rate  example 

^  °>  of  the  excellent  account  to  which  he  can  turn  his  exceptionally  wide  and 

^.jy  varied  information.  .  .   .  Masterly  and  exhaustive." — Pall  Mall  Gazette. 

3-g  IV.  PHYSIOGNOMY  AND  EXPRESSION.  By  P.  MANTE- 
w  cs  GAZZA.  Illustrated. 

~  4)  "  Brings  this  highly  interesting  subject  even  with  the  latest  researches. 

Og  ...  Professor  Mantegazza  is  a  writer  full  of  life  and  spirit,  and  the  natural 
2  X  attractiveness  of  his  subject  is  not  destroyed  by  his  scientific  handling  of  it." 
^<g  — Literary  War  Id  ( Boston). 

^  V.  EVOLUTION  AND  DISEASE.     By  J.  B.  SUTTON,  F.R.C.S. 

wla  With  135  Illustrations. 

jJJ  "The  book  is  as  interesting  as  a  novel,  without  sacrifice  of  accuracy  or 

j  system,  and  is  calculated  to  give  an  appreciation  of  the  fundamentals  of 

Je  •<  "^       pathology  to  the  lay  reader,  while  forming  a  useful  collection  of  illustrations 
J^  Z  ••       of  disease  for  medical  reference.  "—Journal  of  Mental  Science. 

§  IS?  VI.  THE    VILLAGE    COMMUNITY.      By   G.    L.    GOMME. 

P  C*UJ  Illustrated. 

2  ^""'  "  His  book  will  probably  remain  for  some  time  the  best  work  of  reference 

Q  OJOJ  for  facts  bearing  on  those  traces  of  the  village  community  which  have  not 

<  EE  been  effaced  by  conquest,  encroachment,  and  the  heavy  hand  of  Roman 

HH  law."— Scottish  Leader. 
W 

>.          VII.  THE    CRIMINAL.     By    HAVELOCK    ELLIS.     Illustrated 
^  Fourth  Edition,  Revised  and  Enlarged. 

"The   sociologist,    the    philosopher,    the   philanthropist,    the    novelist — 
all,  indeed,  for  whom  the  study  of  human  nature  has  any  attraction — will 
find  Mr.  Ellis  full  of  interest  and  suggestiveness." — Academy. 
* 

New  York  :  CHARLES  SCRIBNER'S  SONS. 


VHL  SANITY  AXD  INSANITY.     By  Dr.  CHARLB*  If] 


"Taken  as  a  whole,  ft  is  the  brightest  book  on  the  physical  side  of 
-eB1aliciencr!mWidrfi.o«ta^--/W?J&^Gk-fc 

IX.  HYPNOTISM.     By  DC  ALBERT  MOLL    New  and  Enbiged 

Edition. 
"  Maries  a  step  of  same  inwntante  io  the  stedr  of  nw  dittos  phnav 

'  -  _ ..  _.._,.. 

•igiLjm  ana  jKyuBuiagicu  promcm  %Uauk  nti.itc  not  y*  iccovofl  •HCB  ^ 

-lc«k»u,t£JS«^fewcridcrfE.Cl«L--Ato«r«.  - 

X.  MANUAL  TRAININa    By  Dr.  C.  M.  WOODWARD,  Dirertot 

of  tb«  Manual  Training  School,  St.  Loais.     Illustrated.  ~- 

Xincfc  2s  no  siuicr  **"frtfT<fy  OB  tibc  "nuliBUtt  tituft  PTOafessoc  VToodwrdL          -^  *~ 


XL  THE   SCONCE  OF  FAIRY  TALES.     By  E.   SIDXKY 

HARTLAXD. 
"M«.    Haitbn^s  book  wffl  via  the 


of  hfes  •hjcd,  which  is  erideat  ihwaghuaL*—  -Sfrdmtir.  '2  — 

XIL  PRIMITIVE  FOLK.     By  ELIE  Rectos.  §< 

::    :'-.e   r..:;.  ,    :•:,.,    .: 


THE  EVOLUTION  OF  MARRIAGE.      By  Professor 


"Amo^thediuiBgaBhed  French 
ne»  has  kng  stood  in 


*  tank.     He  appradxs  the  great  study  of 

man  &ee  from  bias  and  ^17  of  genen&atians.     To  coded,  scradnise,  and 
appraise  fete  is  Ids  chief  bmsinesL     In  the  volnroc  bciore  ns  be  shows  thee 


XIV.  BACTERL\  AND  THEIR  PRODUCTS.      By  Dr.  a 

Sots  WOODHEAD.     Ilhistiated.     Second  Edition. 
-AneaaBeMflHHHnror  the  pRscnt  state  of  kMiriedge  of  thesrf^cel." 


XV.  EDUCATION  AND  HEREDITY.     By  J.  M.  GUVAU.        £  gz 
"ft  is  at  once  a  feolise  on  sodofagj,  ethics,  aad  pedagogics.     It  is  C  ~  :z 

--:-::•.,         .-...-.--.:  -   7- 

':•:  :V          -•  :          -     -  M'=      -       -   •        :    '  • --  "---'  : --      -^     -     '-   I  -| 

<  -* 


XVL  THE  MAN  OF  GENIUS.     By  Prot  LOMBROSO.    IDns-  ? 

> 


New  YoA  :  CHAEtJS  Sc  MBXUl'S  SOKS. 


XVII.  THE   HISTORY  OF   THE    EUROPEAN    FAUNA. 
By  R.  F.  SCHARFF,  B.Sc.,  Ph.D.,  F.Z.S.     Illustrated. 

XVIII.  PROPERTY  :  ITS  ORIGIN  AND  DEVELOPMENT. 
By    CH.     LETOURNEAU,   General    Secretary  to   the  Anthro- 
pological Society,  Paris,  and  Professor  in  the  School  of  Anthro- 
pology, Paris. 

"  M.  Letourneau  has  read  a  great  deal,  and  he  seems  to  us  to  have 
selected  and  interpreted  his  facts  with  considerable  judgment  and  learning." 
—  Westminster  Review. 

XIX.  VOLCANOES,    PAST    AND    PRESENT.       By    Prof. 
EDWARD  HULL,  LL.D.,  F.R.S. 

"  A  very  readable  account  of  the  phenomena  of  volcanoes  and  earth- 
quakes. " — Nature. 

XX.  PUBLIC   HEALTH.      By   Dr.    J.    F.    J.    SYKES.      With 

numerous  Illustrations. 

"Not  by  any  means  a  mere  compilation  or  a  dry  record  of  details  and 
statistics,  but  it  takes  up  essential  points  in  evolution,  environment,  prophy- 
laxis, and  sanitation  bearing  upon  the  preservation  of  public  health." — 
Lancet. 

XXI.  MODERN    METEOROLOGY.     AN   ACCOUNT   OF   THE 
GROWTH  AND   PRESENT  CONDITION    OF  SOME  BRANCHES 
OF  METEOROLOGICAL  SCIENCE.    By  FRANK  WALDO,  Ph.D., 
Member  of  the  German  and  Austrian  Meteorological  Societies, 
etc.;  late  Junior  Professor,  Signal  Service,  U.S.A.     With  112 
Illustrations. 

"  The  present  volume  is  the  best  on  the  subject  for  general  use  that  we 
have  seen." — Daily  Telegraph  (London). 

XXII.  THE  GERM-PLASM  :  A  THEORY  OF  HEREDITY. 

By  AUGUST    WEISMANN,    Professor     in    the    University    of 
Freiburg-in-Breisgau.     With  24  Illustrations.     $2.50. 
"There  has  been  no  work  published  since  Darwin's  own  books  which 
has  so  thoroughly  handled  the  matter  treated  by  him,  or  has  done  so  much 
to  place  in  order  and  clearness  the  immense  complexity  of  the  factors  of 
heredity,  or,  lastly,  has  brought  to  light  so  many  new  facts  and  considerations 
bearing  on  the  subject." — British  Medical  Journal. 

XXIII.  INDUSTRIES  OF  ANIMALS.     By  E.  F.   HOUSSAY. 
With  numerous  Illustrations. 

"  His  accuracy  is  undoubted,  yet  his  facts  out-marvel  all  romance.  These 
facts  are  here  made  use  of  as  materials  wherewith  to  form  the  mighty  fabric 
of  evolution." — Manchester  Guardian. 

New  York  :  CHARLES  SCRIBNER'S  SONS. 


XXIV.  MAN  AND   WOMAN.     By  HAVELOCK   ELLIS.     Illus- 
trated.    Fourth  and  Revised  Edition. 

"  Mr.  Havelock  Ellis  belongs,  in  some  measure,  to  the  continental  school 
of  anthropologists  ;  but  while  equally  methodical  in  the  collection  of  facts, 
he  is  far  more  cautious  in  the  invention  of  theories,  and  he  has  the  further 
distinction  of  being  not  only  able  to  think,  but  able  to  write.  His  book  is 
a  sane  and  impartial  consideration,  from  a  psychological  and  anthropological 
point  of  view,  of  a  subject  which  is  certainly  of  primary  interest." — 
Athenaeum. 

XXV.  THE    EVOLUTION   OF   MODERN    CAPITALISM. 

By  JOHN  A.  HOBSON,  M.A.  (New  and  Revised  Edition.) 
"  Every  page  affords  evidence  of  wide  and  minute  study,  a  weighing  of 
facts  as  conscientious  as  it  is  acute,  a  keen  sense  of  the  importance  of  certain 
points  as  to  which  economists  of  all  schools  have  hitherto  been  confused  and 
careless,  and  an  impartiality  generally  so  great  as  to  give  no  indication  of  his 
[Mr.  Hobson's]  personal  sympathies." — Pall  Mall  Gazette. 

XXVI.  APPARITIONS    AND     THOUGHT  -  TRANSFER- 
ENCE.   By  FRANK  PODMORE,  M.A. 

"A  very  sober  and  interesting  little  book.  .  .  .  That  thought-transfer- 
ence is  a  real  thing,  though  not  perhaps  a  very  common  thing,  he  certainly 
shows. " — Spectator. 

XXVII.  AN      INTRODUCTION      TO      COMPARATIVE 
PSYCHOLOGY.    By  Professor  C.  LLOYD  MORGAN.    With 
Diagrams. 

"  A  strong  and  complete  exposition  of  Psychology,  as  it  takes  shape  in  a 
mind  previously  informed  with  biological  science.  .  .  .  Well  written,  ex- 
tremely entertaining,  and  intrinsically  valuable." — Saturday  Review. 

XXVIII.  THE  ORIGINS  OF  INVENTION :   A    STUDY    OF 
INDUSTRY  AMONG  PRIMITIVE  PEOPLES.    By  OTIS  T.  MASON, 
Curator  of  the  Department  of  Ethnology  in  the  United  States 
National  Museum. 

"A  valuable  history  of  the  development  of  the  inventive  faculty."— 
Nature. 

XXIX.  THE    GROWTH   OF   THE   BRAIN:    A  STUDY  OF 
THE  NERVOUS  SYSTEM  IN  RELATION  TO  EDUCATION.    By 
HENRY  HERBERT  DONALDSON,  Professor  of  Neurology  in  the 
University  of  Chicago. 

"  We  can  say  with  confidence  that  Professor  Donaldson  has  executed  his 
work  with  much  care,  judgment,  and  discrimination."—  The  Lancet. 

XXX.  EVOLUTION    IN    ART:    As    ILLUSTRATED    BY  THE 
LIFE-HISTORIES   OF    DESIGNS.      By  Professor  ALFRED  C. 
HADDON.     With  130  Illustrations. 

"It  is  impossible  to  speak  too  highly  of  this  most  unassuming  and 
invaluable  book."— Journal  of  Anthropological  Institute. 

New  York  :  CHARLES  SCRIBNER'S  SONS. 


XXXI.  THE   PSYCHOLOGY   OF   THE   EMOTIONS.      By 
TH.  RlBOT,  Professor  at  the  College  of  France,  Editor  of  the 
Revue  Philosophique. 

"Professor  Ribot's  treatment  is  careful,  modern,  and  adequate." — 
Academy. 

XXXII.  HALLUCINATIONS  AND  ILLUSIONS:  A  STUDY 
OF  THE  FALLACIES  OF  PERCEPTION.    By  EDMUND  PARISH. 

"  This  remarkable  little  volume." — Daily  News. 

XXXIII.  THE  NEW  PSYCHOLOGY.     By  E.  W.  SCRIPTURE, 
Ph.D.  (Leipzig).     With  124  Illustrations. 

XXXIV.  SLEEP :  ITS  PHYSIOLOGY,  PATHOLOGY,  HYGIENE,  AND 
PSYCHOLOGY.    BY  MARIE  DE  MANACEINE  (St.  Petersburg). 
Illustrated. 

XXXV.  THE     NATURAL    HISTORY    OF     DIGESTION. 
By  A.    LOCKHART  GILLESPIE,   M.D.,  F.R.C.P.    ED.,   F.R.S. 
ED.     With  a  large  number  of  Illustrations  and  Diagrams. 

"  Dr.  Gillespie's  work  is  one  that  has  been  greatly  needed.  No  com- 
prehensive collation  of  this  kind  exists  in  recent  English  Literature." — 
American  Journal  of  the  Medical  Sciences. 

XXXVI.  DEGENERACY :  ITS  CAUSES,  SIGNS,  AND  RESULTS. 
By   Professor  EUGENE  S.   TALBOT,   M.D.,   Chicago.      With 
Illustrations. 

"The  author  is  bold,  original,  and  suggestive,  and  his  work  is  a  con- 
tribution of  real  and  indeed  great  value,  more  so  on  the  whole  than  anything 
that  has  yet  appeared  in  this  country." — American  Journal  of  Psychology. 

XXXVII.  THE  RACES   OF   MAN:    A   SKETCH  OF   ETHNO- 
GRAPHY AND  ANTHROPOLOGY.    By  J.  DENIKER.    With  178 
Illustrations. 

"Dr.  Deniker  has  achieved  a  success  which  is  well-nigh  phenomenal." — 
British  Medical  Journal. 

XXXVIII.  THE     PSYCHOLOGY    OF     RELIGION.       AN 
EMPIRICAL  STUDY  OF  THE  GROWTH  OF   RELIGIOUS  CON- 
SCIOUSNESS.   By  EDWIN  DILLER  STARBUCK  Ph.D.,  Assistant 
Professor  of  Education,  Leland  Stanford  Junior  University. 

"No  one  interested  in  the  study  of  religious  life  and  experience  can 
afford  to  neglect  this  volume." — Morning  Herald. 

XXXIX.  THE  CHILD  :  A  STUDY  IN  THE  EVOLUTION  OF  MAN. 
By  Dr.  ALEXANDER  FRANCIS  CHAMBERLAIN,  M.A.,  Ph.D., 
Lecturer  on   Anthropology   in    Clark    University,    Worcester 
(Mass.).     With  Illustrations. 

"The  work  contains  much  curious  information,  and  should  be  studied  by 
those  who  have  to  do  with  children."—  Sheffield  Daily  Telegraph. 

New  York :  CHARLES  SCRIBNER'S  SONS. 


XL.  THE  MEDITERRANEAN  RACE.     By  Professor  SERGL 

\\  ith  over  100  Illustrations. 

"  M.  Sergi  has  given  m  a  hvad  awl  complete  exposition  of  his  views  on  a 
abject  of  supreme  interest/' — Irish  Trmus. 

XLL  THE  STUDY  OF  RELIGION.   By  MORRIS  JASIROW. 

JUBL,  PhJX,  Professor  in  the  University  of  Pennsylvania. 
"This  work  presents  a  careful  survey  of  the  sabject,  and  forms  mm 


XLIL  HISTORY  OF  GEOLOGY  AND  PALEONTOLOGY 
TO  THE  END  OF  THE  NINETEENTH  CENTURY. 
By  KARL  vox  ZITTEL. 

:  It  is  a  rery  mastcriy  liraihr,  mutlat  will  a  wide  grasp  of 
"  s.s— Pmt&s&erf  ( 


XLJIL  THE  MAKING  OF  CITIZENS :  A  STUDY  DC  COM- 
PARATIVE EDUCATION.  By  R.  E.  HUGHES,  M_A.  (Oxon.), 
RSo  Lend.). 

"Mr.  H^hes  gives  a  l*dd  acoonnt  of  the  exact  ] 
England,  Germany,  Facce.  and  the  United 
present  a  dear  and  attractive  picture  of  the  manner  in  which  one  of  the 
greatest  awab«B  BOW  at  kne  kbemg  soHed  both  at  home  and  abroad.1" 
—StaM^rd. 

XLJV.   MORALS:  A  TREATISE  ox  THE  PSYCHO-SOCIOLOGICAL 
BASES  OF  ETHICS.    By  PROFESSOR  G.  L.  DUPRAT.    Trans- 
lated by  W.  J.  GREEXSTREET,  M^,  F.R-A.& 
'•  The  present  work  is  representatrrc  of  Ac  modern  departnre  in  the 
treatment  of  the  theory  of  morals.     The  aether  brings  a  wide  knowledge 
to  bear  on  his  sabject.1*— EimaHm. 

XLV.    A    STUDY    OF    RECENT    EARTHQUAKES.      By 
CHARLES  DAVTSOX,  D.Sc^  F.G.S.    \\  ith  liUrUiations. 
"  Dr.  Danson  has  done  his  work  wdL" — WlntmnuUf  GaatOe, 

XLVI.  MODERN  ORGANIC  CHEMISTRY.  By  DR.  C  A. 
KEAXE,  D.So,  PaD^,  F.LC  Whh  Diagrams. 

TohunepiOTidesaninstnctrreand  s^gestrre  sanej  of  the  great 


TO-DAY'S  ADDITIONS  :- 

THE   CRIMINAL.      By  HAYELOCK  ELLIS.     Fourth  Edition, 

Revised  and  Enlarged. 
XLYII.   THE  JEWS :  A  STUDY  OF  RACE  AXD  EXYTRONMEXT. 

By  Dr.   MAURICE  FlSHBERG. 
"It  shows  abomvfiag  evidence rnksprnjes that  k  kmteaded  to  show, 

ftmmwBm*nC^     *fm*1n%f  tT      f  JUHJlm»mmJlg    y^mo^  TASK    titCTXIT   ^*wJJ    Ct»tl<lif^|    lfV"1|fTy^, 

ft  contains,  to  be  'sare,  anch  infbrnmion  of  great  vame,  and  it  sets  forth 
many  facts  absorbing  in  their  interest  for  any  who  desire  to  study  the 


absorbing 
Jewbh  peopled— /««*  Ck?w:lc. 


New  York:  CHAKUS  SCUBXKR'S  Sojss. 


IBSEN'S    DRAMAS. 

EDITED   BY  WILLIAM   ARCHER. 

THREE     PLAYS    TO    THE     VOLUME. 

i2mo,  CLOTH,  PRICE  $1.25  PER  VOLUME. 

"  We  seem  at  last  to  be  shown  men  and  women  as  they  are  ;  and  at  fint  it 
is  more  than  we  can  endure.  .  .  .  All  Ibsen's  characters  speak  and  act  as  if 
they  were  hypnotised,  and  under  their  creator's  imperious  demand  to  reveal 
themselves.  There  never  was  such  a  mirror  held  up  to  nature  before :  it  is 
too  terrible.  .  .  .  Yet  we  must  return  to  Ibsen,  with  his  remorseless  surgery , 
his  remorseless  electric- light ',  until  we,  too,  have  grown  strong  and  learned  to 
face  the  naked — if  necessary,  the  flayed  and  bleeding— reality." — SPEAKER 
(London). 

VOL.  I.  "A  DOLL'S  HOUSE,"  "THE  LEAGUE  OF 
YOUTH,"  and  "THE  PILLARS  OF  SOCIETY."  With 
Portrait  of  the  Author,  and  Biographical  Introduction  by 

WlLLIAMARCHER. 

VOL.  II.  "GHOSTS,"  "AN  ENEMY  OF  THE  PEOPLE," 
and  "THE  WILD  DUCK."  With  an  Introductory  Note. 

ft>L.  III.  "LADY  INGER  OF  OSTRAT,"  "THE  VIKINGS 
AT  HELGELAND,"  "THE  PRETENDERS."  With  an 
Introductory  Note, 

VOL.  IV.  "EMPEROR  AND  GALILEAN."  With  an 
Introductory  Note  by  WILLIAM  ARCHER. 

VOL.  V.  "ROSMERSHOLM,"  "THE  LADY  FROM  THE 
SEA,"  "HEDDA  GABLER."  Translated  by  WILLIAM 
ARCHER.  With  an  Introductory  Note. 

VOL.  VI.  "PEER  GYNT:  A  DRAMATIC  POEM." 
Authorised  Translation  by  WILLIAM  and  CHARLES  ARCHER. 

The  sequence  of  the  plays  in  each  volume  is  chronological ;  the  complete 
set  of  volumes  comprising  the  dramas  thus  presents  them  in  chronological 
order. 

"  The  art  of  prose  translation  does  not  perhaps  enjoy  a  very  high  literary 
status  in  England,  but  we  have  no  hesitation  in  numbering  the  present 
version  of  Ibsen,  so  far  as  it  has  gone  (Vols.  I.  and  II.),  among  the  very 
best  achievements,  in  that  kind,  of  our  generation." — Academy. 

"We  have  seldom,  if  ever,  met  with  a  translation  so  absolutely 
Idiomatic." — Glasgow  Herald. 


New  York :  CHARLES  SCRIBNER'S  SONS. 


AA    000869604    9 


